Image processing device

ABSTRACT

An image processing apparatus of correcting the color of a specific range of a pixel signal for each pixel included in an input image signal, comprises an intensity determination means of generating a correction intensity that is small on the periphery of the color region of the specific range on the basis of two chromaticity signals excluding a luminance component and large in the vicinity of the nearly central portion of the range in the pixel signal, a target color setting means of setting a target color depending on which the pixel signal is corrected, a correction degree setting means of setting correction degree by also using information, other than pixel information, included in the pixel signal, and a correction means of making the image signal close to the target color depending on the correction intensity output from the intensity determination means and the correction degree output from the correction degree setting means.

This application is a U.S. national phase application of PCTinternational application PCT/JP2003/011604.

TECHNICAL FIELD

The present invention relates to an image processing apparatus, an imageprocessing method, a program, a recording medium, a printer apparatus, atelevision receiver, a projector apparatus, a photographing apparatusand a mobile communication terminal. More particularly, the presentinvention relates to a memory color correction technology ofautomatically converting the color in a specific region of an inputimage signal into a more desirable color. The present invention iswidely applicable to output devices, such as a display and a printer,input devices, such as a digital camera and a digital camcorder, and PCapplication software being used for photographic image databases andretouching.

BACKGROUND ART

In the prior art, there were insufficiencies in the color correctiontechnologies required for numerous full-color devices, such as a camera,a display and a printer, more specifically, the color correctiontechnologies of correcting the inherent characteristics of devices, suchas the spectroscopic characteristic of a CCD in a camera and thespectroscopic characteristic of ink in a printer, were being developed,the correction accuracy of the above-mentioned color correction wasinsufficient. Thus, the technologies conventionally referred to asselective color adjustment and memory color correction were intended tocorrect improper color reproduction owing to the insufficient accuracy.

The characteristics inherent in the devices have been accuratelycorrected quantitatively owing to the development of the colorcorrection technology in recent years. Considerably faithful colorreproduction has been attained in the sense that the colorsquantitatively close to those of an object can be displayed or printed.

However, the use of digital cameras has become widespread andsubstituted for silver salt analog photographs. High-quality picturetechnologies that were impossible for analog silver salt photographshave been achieve using technologies of selective color adjustment andmemory color correction having target levels higher than previouslevels. This is because a camera photographing a natural world isdifferent from a copier wherein faithfulness to manuscripts isimportant. Displaying on a display and printing on paper are differentfrom photographing an object with respect to physical shape and absolutesize, light source and the time of photographing being separate from thetime of reproduction. It is known that a quantitatively approximatecolor is not necessarily sensed to be visually approximate. Hence, forthe purpose of displaying and printing a beautiful image that can beobtained only using digital technology, a correction technology formemory colors, such as sky blue, human skin color and the green oftrees, becomes important.

However, in the circumstances where quantitatively faithful colorreproduction has been attained, how to eliminate the side effects ofmemory color correction more sufficiently than ever before has becomeimportant. More specifically, for example, the following points areimportant: (1) eliminating influence to regions other than the target tobe corrected in terms of memory color, (2) the continuity (no colorjumping) of gradation in the directions of luminance, saturation and huein a memory color region and the boundary between the inside and outsidethe memory color region, and (3) reducing influence to other objects inthe memory color region.

In Japanese Laid-open Patent Application No. Sho 62-281062, the color inthe skin color region having the largest number of pixels is correctedto a desirable skin color, wherein the number of pixels in the skincolor region of an image is counted and the execution of correction isswitched depending on whether the number of pixels in the skin colorregion exceeds a predetermined value or not. In Japanese Laid-openPatent Application No. Hei 02-96477 and Japanese Laid-open PatentApplication No. Hei 06-78320, the correction target region is narrowedwith respect to hue and saturation, whereby correction not extended toregions other than the correction region is attained.

The entire disclosures of Japanese Laid-open Patent Application No. Sho62-281062, Japanese Laid-open Patent Application No. Hei 02-96477 andJapanese Laid-open Patent Application No. Hei 06-78320 are incorporatedherein by reference in their entirety.

In Japanese Laid-open Patent Application No. Sho 62-281062,correction/no-correction is switched using the number of pixels in askin color region; however, when the number of pixels in the skin colorregion is few, correction is not carried out, and when the number ofpixels is large, correction is carried out for the color in the skincolor region by the same amount. More specifically, the color judged tobe inside the skin color region is subjected to the same amount ofcorrection in the same direction regardless of whether the color isdeviated in either direction from the reference color being setempirically. Hence, there is a color that is corrected in a directionopposite to the desirable direction. Such a color becomes discontinuousat the boundary of the region and causes color jumping.

In Japanese Laid-open Patent Application No. Hei 02-96477, a correctionregion and the weight of correction are calculated according to theproduct of hue and saturation weighting functions, and hue, saturationand luminance are corrected by the amount proportional to the weight.Color continuity can be maintained by gently setting the weightingfunction in a wide range. However, the correction direction inside thecorrection region is still the same direction, and there is a color thatis corrected in a direction opposed to the desirable correctiondirection.

In Japanese Laid-open Patent Application No. Hei 06-78320, a correctionregion and the weight of correction are calculated using the minimumvalue of two weighting functions being orthogonal in a chromaticityplane, and the hue, saturation and luminance are shifted by the amountproportional to the weight, whereby it can be expected to have an effectof memory color correction; however, because the correction is carriedout in a rectangular region in the chromaticity plane, it is difficultto narrow the regions of skin color and sky blue necessarily andsufficiently; if the effect is exerted, a side effect of correctingcolors that should not be changed essentially is caused. In addition, ifthe size of the rectangular region is made smaller, the influence tocolors other than the target color can be avoided, but changes in hueand saturation occurs in the target color, whereby the effect of memorycolor correction is lost.

The above-mentioned prior art has carry out memory color correction butwith side effects. Since the color correction technologies of correctingthe inherent characteristics of devices were being developed asdescribed above, the correction accuracy of the above-mentioned colorcorrection was insufficient. The color regions unable to be correctedproperly because of such reasons were corrected as a whole in thosedays.

Hence, a side effect is caused of correcting colors that should not becorrected essentially. In addition, it is inevitable that other objectsincluded in the memory color region that should be corrected essentiallybut accidentally having colors close to the color to be corrected arecorrected. Furthermore, gradation is apt to become discontinuous, andcolor jumping occurs, whereby image quality degradation may be caused,beyond the effect of memory color correction.

DISCLOSURE OF THE INVENTION

In consideration of the above-mentioned problems, the present inventionis intended to provide an image processing apparatus, an imageprocessing method, a program, a recording medium, a printer, atelevision receiver, a projector apparatus, a photographing apparatusand a mobile communication terminal not causing a side effect ofcorrecting colors that should not be subjected to memory colorcorrection essentially.

Furthermore, in consideration of the above-mentioned problems, thepresent invention is intended to provide an image processing apparatus,an image processing method, a program, a recording medium, a printer, atelevision receiver, a projector apparatus, a photographing apparatusand a mobile communication terminal capable of avoiding correcting otherobjects included in the memory color region that should be correctedessentially but accidentally having colors close to the color to becorrected.

Still further, in consideration of the above-mentioned problems, thepresent invention is intended to provide an image processing apparatus,an image processing method, a program, a recording medium, a printer, atelevision receiver, a projector, a photographing apparatus and a mobilecommunication terminal not making gradation discontinuous and notcausing color jumping.

For the purpose of solving the above-mentioned problems, a first aspectof the present invention is an image processing apparatus of correctingthe color of a predetermined range of a pixel signal for each pixelincluded in an input image signal, comprising:

target color setting means of setting a target color depending on whichthe color of said pixel signal is corrected, and

Color conversion means of carrying out correction to make the color ofsaid pixel signal coincident with or close to said target color by usingsaid pixel signal, information of identifying a photographic scene byalso using information, other than pixel information, included in saidpixel signal, and said target color.

Furthermore, a second aspect of the present invention is an imageprocessing apparatus of correcting the color of a predetermined range ofa pixel signal for each pixel included in an input image signal,comprising:

target color setting means of setting a target color depending on whichthe color of said pixel signal is corrected, and

color conversion means of carrying out correction to make the color ofsaid pixel signal coincident with or close to said target color by usingthe luminance component in the color of said pixel signal, twochromaticity components excluding said luminance component in the colorof said pixel signal, and said target value, wherein

said color conversion means determines said correction degree by usingnot only said two chromaticity components of said pixel signal to becorrected but also said luminance component of said pixel signal to becorrected.

Furthermore, a third aspect of the present invention is the imageprocessing apparatus in accordance with the first aspect of the presentinvention, wherein said color conversion means comprises:

intensity determination means of generating a correction intensity thatis small on the periphery of the color region of said specific range seton the basis of two chromaticity components excluding the luminancecomponent in the color of said pixel signal and large in the vicinity ofthe central portion of said region,

correction degree setting means of setting a correction degree by alsousing information, other than pixel information, included in said pixelsignal, and

correction means of making the color of said pixel signal coincidentwith or close to said target color depending on said correctionintensity having been generated and said correction degree having beenset, wherein

said correction degree setting means sets said correction degree byidentifying at least an image photographing scene according to saidinput image signal.

Furthermore, a fourth aspect of the present invention is an imageprocessing apparatus in accordance with the second aspect of the presentinvention, wherein said color conversion means comprises:

intensity determination means of generating a correction intensity thatis small on the periphery of the color region of said specific range seton the basis of the luminance component and the two chromaticitycomponents excluding said luminance component in the color of said pixelsignal and large in the vicinity of the central portion of said region,and

correction means of making the color of said pixel signal coincidentwith or close to said target color depending on said correctionintensity having been generated.

Furthermore, a fifth aspect of the present invention is an imageprocessing apparatus in accordance with the fourth aspect of the presentinvention, wherein said intensity determination means comprises:

first function generation means of outputting a candidate of a firstcorrection intensity for said luminance signal,

second and third function generation means of outputting candidates ofsecond and third correction intensities for said two chromaticitycomponents, respectively, and

synthesizing means of synthesizing the candidates of said first, secondand third correction intensities and outputting the result as saidcorrection intensity.

Still further, a sixth aspect of the present invention is the imageprocessing apparatus in accordance with the fourth aspect of the presentinvention, wherein said intensity determination means comprises:

first function generation means of outputting a candidate of a firstcorrection intensity for said luminance signal,

two-dimensional function generation means of outputting a secondcorrection intensity on the basis of a two-dimensional function typifiedby an ellipse using said two chromaticity components, and

synthesizing means of synthesizing the candidates of said first andsecond correction intensities and outputting the result as saidcorrection intensity.

Still further, a seventh aspect of the present invention is the imageprocessing apparatus in accordance with the fourth aspect of the presentinvention, wherein said intensity determination means comprises:

first function generation means of outputting a candidate of a firstcorrection intensity for said luminance signal,

first polar coordinate conversion means of converting said twochromaticity components into a hue signal and a saturation signal,

second function generation means of outputting a candidate of a secondcorrection intensity for said hue signal,

third function generation means of outputting a candidate of a thirdcorrection intensity for said saturation signal, and

synthesizing means of synthesizing the candidates of said first, secondand third correction intensities and outputting the result as saidcorrection intensity.

Still further, an eighth aspect of the present invention is the imageprocessing apparatus in accordance with the third or fourth aspect ofthe present invention, wherein said correction means corrects each ofsaid two chromaticity components to a value obtained when each of saidtwo chromaticity components and two target chromaticity values outputfrom said target color setting means are internally divided depending onsaid correction intensity.

Still further, a ninth aspect of the present invention is the imageprocessing apparatus in accordance with the third or fourth aspect ofthe present invention, wherein

said correction means has second polar coordinate conversion means ofconverting said two chromaticity components into a hue signal and asaturation signal, and

said correction means corrects said hue signal and said saturationsignal output from said second polar coordinate conversion means to avalue obtained when said hue signal and said saturation signal and thetarget hue signal and the target saturation signal output from saidtarget color setting means are internally divided depending on saidcorrection intensity.

Still further, a 10th aspect of the present invention is the imageprocessing apparatus in accordance with the third or fourth aspect ofthe present invention, wherein

said intensity determination means outputs a hue correction intensityfor hue correction and a saturation correction intensity for saturationcorrection,

said correction means has second polar coordinate conversion means ofconverting said two chromaticity components into a hue signal and asaturation signal,

hue correction means of correcting said hue signal having been convertedto a value obtained when said hue signal and the target hue value outputfrom said target color setting means are internally divided depending onsaid hue correction intensity, and

saturation correction means of correcting said saturation signal havingbeen converted to a value obtained when said saturation signal and thetarget saturation value output from said target color setting means areinternally divided depending on said saturation correction intensity.

Still further, an 11th aspect of the present invention is the imageprocessing apparatus in accordance with the third aspect of the presentinvention, wherein said correction degree setting means determines saidcorrection degree according to said input image signal and photographicinformation at the time when an input image is taken.

Still further, a 12th aspect of the present invention is the imageprocessing apparatus in accordance with the 11th aspect of the presentinvention, wherein said correction degree setting means comprises:

image identification means of identifying the photographic scene of animage according to said input image signal,

photographic information identification means of identifying aphotographic scene according to the photographic information at the timewhen said input image signal is photographed, and

correction degree determination means of determining said correctiondegree according to the outputs of said image identification means andsaid image information identification means.

Still further, a 13th aspect of the present invention is the imageprocessing apparatus in accordance with the 12th aspect of the presentinvention, wherein said image identification means and said photographicinformation identification means identify whether a person is includedin an image or not.

Still further, a 14th aspect of the present invention is the imageprocessing apparatus in accordance with the 12th aspect of the presentinvention, wherein said image identification means and said photographicinformation identification means identify whether the sky is included inan image or not.

Still further, a 15th aspect of the present invention is the imageprocessing apparatus in accordance with the 12th aspect of the presentinvention, wherein said image identification means and said photographicinformation identification means identify whether green plants areincluded in an image or not.

Still further, a 16th aspect of the present invention is the imageprocessing apparatus in accordance with the first or second aspect ofthe present invention, comprising:

means of interpolating a three-dimensional look-up table of using threeinput signals as addresses and outputting three output signals orinterpolating two of said three-dimensional look-up tables, wherein

the correspondence relationship of making the color of said pixel signalto correspond to the color corrected using said color conversion meansis stored in said three-dimensional look-up table in advance, and

the color of said each pixel signal is corrected using saidthree-dimensional look-up table.

Still further, a 17th aspect of the present invention is an imageprocessing method of correcting the color of a predetermined range of apixel signal for each pixel included in an input image signal,comprising:

a target color setting step of setting a target color depending on whichthe color of said pixel signal is corrected, and

a color conversion step of carrying out correction to make the color ofsaid pixel signal coincident with or close to said target color by usingsaid pixel signal, information of identifying a photographic scene byalso using information, other than pixel information, included in saidpixel signal, and said target color.

Still further, an 18th aspect of the present invention is an imageprocessing method of correcting the color of a predetermined range of apixel signal for each pixel included in an input image signal,comprising:

a target color setting step of setting a target color depending on whichthe color of said pixel signal is corrected, and

a color conversion step of carrying out correction to make the color ofsaid pixel signal coincident with or close to said target color by usingthe luminance component in the color of said pixel signal, twochromaticity components excluding said luminance component in the colorof said pixel signal, and said target value.

Still further, a 19th aspect of the present invention is a program ofthe image processing apparatus in accordance with the first aspect ofthe present invention, the program being used to operate a computer as:

target color setting means of setting the target color depending onwhich the color of said pixel signal is corrected, and

color conversion means of carrying out correction to make the color ofsaid pixel signal coincident with or close to said target color by usingsaid pixel signal, information of identifying a photographic scene byalso using information, other than pixel information, included in saidpixel signal, and said target color.

Still further, a 20th aspect of the present invention is a program ofthe image processing apparatus in accordance with the second aspect ofthe present invention, the program being used to operate a computer as:

target color setting means of setting the target color depending onwhich the color of said pixel signal is corrected, and

color conversion means of carrying out correction to make the color ofsaid pixel signal coincident with or close to said target color by usingthe luminance component in the color of said image signal, twochromaticity components excluding said luminance component in the colorof said pixel signal, and said target value.

Still further, a 21st aspect of the present invention is a recordingmedium having a program in accordance with the 19th or 20th aspect ofthe present invention, said recording medium being processable using acomputer.

Still further, a 22nd aspect of the present invention is a printercomprising:

input means of inputting an image signal,

image processing means of image processing the image signal having beeninput, and

printing means of printing said image signal having been image processedon paper media, wherein

the image processing apparatus in accordance with the first or secondaspect of the present invention is used for said image processing means.

Still further, a 23rd aspect of the present invention is a televisionreceiver comprising:

receiving means of receiving an image signal being broadcast, and

image processing means of image processing the image signal output fromsaid receiving means, wherein

said image signal having been image processed is displayed on displaymeans, and

the image processing apparatus in accordance with the first or secondinvention of the present invention is used for said image processingmeans.

Still further, a 24th aspect of the present invention is a projectorapparatus comprising:

input means of inputting an image signal,

image processing means of image processing the image signal having beeninput, and

projection means of projecting said image signal having been imageprocessed on a screen, wherein

the image processing apparatus in accordance with the first or secondinvention of the present invention is used for said image processingmeans.

Still further, a 25th aspect of the present invention is a photographingapparatus comprising:

photographing means of photographing an image, and

image processing means of image processing said image signal output fromsaid photographing means, wherein

the image processing apparatus in accordance with the first or secondinvention of the present invention is used for said image processingmeans.

Still further, a 26th aspect of the present invention is a mobilecommunication terminal comprising:

a wireless communication circuit of outputting broadcast waves to anantenna and of inputting a received signal from the antenna,

image processing means of image processing the image signal included insaid received signal, and

display means of displaying said image signal having been imageprocessed, wherein

the image processing apparatus in accordance with the first or secondinvention of the present invention is used for said image processingmeans.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a configuration of an image processingapparatus in accordance with Embodiment 1 of the present invention;

FIG. 2( a) is a view showing a skin color region synthesized using asynthesizing means in accordance with Embodiment 1 of the presentinvention;

FIG. 2( b) is a view showing an example of a function generation meansregarding L* signal in accordance with Embodiment 1 of the presentinvention;

FIG. 2( c) is a view showing an example of a function generation meansregarding a* signal in accordance with Embodiment 1 of the presentinvention;

FIG. 2( d) is a view showing an example of a function generation meansregarding b* signal in accordance with Embodiment 1 of the presentinvention;

FIG. 3 is a block diagram showing a configuration of an image processingapparatus in accordance with Embodiment 2 of the present invention;

FIG. 4 is a view showing an example of a two-dimensional functiongeneration means of generating correction intensity Wc in accordancewith Embodiment 2 of the present invention;

FIG. 5 is a block diagram showing a configuration of an image processingapparatus in accordance with Embodiment 3 of the present invention;

FIG. 6( a) is a view showing a sky blue region wherein correctionintensity W in three dimensions is synthesized using a synthesizingmeans in accordance with Embodiment 3 of the present invention;

FIG. 6( b) is a view showing an example of an LUT constituting afunction generation means regarding luminance L* in accordance withEmbodiment 3 of the present invention;

FIG. 6( c) is a view showing an example of an LUT constituting afunction generation means regarding hue in accordance with Embodiment 3of the present invention;

FIG. 6( d) is a view showing an example of an LUT constituting afunction generation means regarding sat in accordance with Embodiment 3of the present invention;

FIG. 7 is a block diagram showing a configuration of an image processingapparatus in accordance with Embodiment 4 of the present invention;

FIG. 8 is an explanatory view of the effect of the correction means inaccordance with Embodiment 4 of the present invention;

FIG. 9 is a block diagram showing a configuration of an image processingapparatus in accordance with Embodiment 5 of the present invention;

FIG. 10( a) is a view showing an example of a saturation-use functiongeneration means 210E constituting an intensity determination means 201Cin accordance with Embodiment 5 of the present invention;

FIG. 10( b) is a view showing an example of a saturation-use functiongeneration means 210E constituting an intensity determination means 202Cin accordance with Embodiment 5 of the present invention;

FIG. 11 is a block diagram showing a configuration of an imageprocessing apparatus in accordance with Embodiment 6 of the presentinvention;

FIG. 12( a) is a view showing an example of a color image to be input inaccordance with Embodiment 6 of the present invention;

FIG. 12( b) is a view showing an example of the result obtained when skyregion candidate detection is carries out in accordance with Embodiment6 of the present invention;

FIG. 12( c) is a view showing an example of a sky region judgment maskin accordance with Embodiment 6 of the present invention;

FIG. 12( d) is a view showing the result obtained when the sky regionjudgment mask of FIG. 12( c) is applied to the result obtained when thesky region detection of FIG. 12( b) is carried out in accordance withEmbodiment 6 of the present invention;

FIG. 13 is a block diagram showing a configuration of an imageprocessing apparatus in accordance with Embodiment 7 of the presentinvention;

FIG. 14 is a block diagram showing a configuration of a printer inaccordance with Embodiment 8 of the present invention;

FIG. 15 is a block diagram showing a configuration of a televisionreceiver (projector) in accordance with Embodiment 8 of the presentinvention;

FIG. 16 is a block diagram showing a configuration of a video moviecamera (digital camera) in accordance with Embodiment 8 of the presentinvention;

FIG. 17 is a block diagram showing a configuration of a portabletelephone in accordance with Embodiment 8 of the present invention;

FIG. 18( a) is an explanatory view of a turn-back in the case of onedimension wherein one output corresponds the one input, two inputs, orthree inputs; and

FIG. 18( b) is an explanatory view of a turn-back in the(a*, b*) planein accordance with Embodiment 2 of the present invention.

EXPLANATIONS OF NUMERALS

100A, 100B, 100C, 100D, 100E, 100F, 100G memory color correction means

200A, 200B, 200C, 201C, 202C intensity determination means

210A, 210B, 210C, 210D, 210E function generation means

211 two-dimensional function generation means

220, 221, 222 synthesizing means

230, 320 polar coordinate conversion means

300A, 300B correction means

310A, 310B internal division operation means

330 orthogonal coordinate conversion means

400A, 400B target color setting means

500 multiplication means

600, 600A, 600B correction degree setting means

610A sky image identification means

611 region information calculation means

612 sky region candidate detection means

613 sky region distribution judgment means

610B person image identification means

620A, 620B photographic information identification

630A, 630B correction degree determination means

700 luminance chromaticity conversion means

710 luminance chromaticity inverse conversion means

900 memory

800 memory card

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments in accordance with the present invention will be describedbelow using the drawings.

Embodiment 1

FIG. 1 is a block diagram showing a schematic configuration of an imageprocessing apparatus in accordance with Embodiment 1 of the presentinvention. The image processing apparatus in accordance with thisembodiment is configured as a unit of carrying out the memory colorcorrection of skin color and installed in a color printer wherein amemory card storing images taken using a digital camera is input anddigital photographs are printed. Hence, a card reader, a JPEGdevelopment processor, a page memory, a print engine, etc., not shown,other than the devices shown in this block diagram, are present. Inaddition, in this embodiment, input and output pixel signals are (R, G,B) signals, and luminance chromaticity signals are (L*, a*, b*).

Numeral 100A designates a memory color correction means, numeral 700designates a luminance chromaticity conversion means of converting pixelsignals comprising (R, G, B) into luminance chromaticity signals (L*,a*, b*), numeral 710 designates a luminance chromaticity inverseconversion means of converting (L*, a*, b*)* corrected using the memorycolor correction means 100A into (R1, G1, B1), and numeral 600designates a correction degree setting means of setting correctiondegree K depending on which memory color correction is carried out usinga means not shown in this embodiment. The correction degree settingmeans 600 will be described later.

In addition, the memory color correction means 100A comprises anintensity determination means 200A of determining correction intensity Waccording to (L*, a*, b*), a target color setting means 400A of settingtarget chromaticity (a0*, b0*) for memory color correction, amultiplication means 500 of multiplying correction intensity W by thecorrection degree K, and a correction means 300A of bringing thechromaticity signals (a*, b*) output from the luminance chromaticityconversion means 700 to the chromaticity values (a0*, b0*) set using thetarget color setting means 400A depending on the output of themultiplication means 500.

Furthermore, the intensity determination means 200A comprises threefunction generation means 210A, 210B and 210C and a synthesizing means220, and the correction means 300A comprises two internal division means310A and 310B.

Regarding the image processing apparatus configured as described abovein accordance with Embodiment 1, its operation will be described below.

The image processing apparatus in accordance with this embodimentcarries out the memory color correction of an input image signal.Herein, with respect to memory colors, colors that should be or aredesired to be like these psychologically, such as skin color and thegreen of trees, are referred to as memory colors. Even if a photographin which human skin color and the green of trees are faithfullyreproduced in color is seen, a user may not be satisfied occasionally.This is because colors different from the human skin color and the greenof trees memorized by the user have been reproduced. In this kind ofcase, by carrying out color reproduction so that the human skin colorand the green of trees become close to the memory colors, the userbecomes to be satisfied with these colors. The image processingapparatus in accordance with this embodiment corrects, for example, thehuman skin color of the input image signal so as to become close to thememory color.

First, the input (R, G, B) signals are converted into a luminance signalL* and two chromaticity signals (a*, b*) using the luminancechromaticity conversion means 700. The L*, a* and b* signals areprocessed using the function generation means 210C, 210A and 210B formedof a look-up table (hereinafter referred to as LUT), and correctionintensities WL, Wa and Wb respectively independent in axial directionsare output. Furthermore, these correction intensities WL, Wa and Wb aresynthesized using the synthesizing means 220 and converted intocorrection intensity W. The synthesizing means 220 in accordance withthis embodiment carries out operation of outputting the minimum value ofWL, Wa and Wb. Hence, the weight W for a skin color region can bedetermined fairly flexibly using the three one-dimensional functiongeneration means 210A, 210B and 210C.

FIGS. 2( d), 2(b) and 2(c) show an example of the LUT for the L* and(a*, b*) signals, and the positive value ranges of the correctionintensities WL, Wa and Wb determine the skin color regions in respectiveaxial directions. FIG. 2( a) shows the skin color region determinedusing the three-dimensional correction intensity W synthesized using thesynthesizing means 220 in the (a*, b*) plane. In other words, the skincolor region in FIG. 2( a) is the region of the (a*, b*) plane in whichthe correction intensity W has a positive value. In this figure, theskin color region is shown, but the correction intensity W is not shown.

The size of the skin color region is determined on the basis of thestatistics of various human skin colors actually photographed, and themagnitude of the weight on each axis inside the region is created byconsidering the pull-in degree to the target color (a0*, b0*) for theabove-mentioned numerous images. According to statistical results, theskin color region occupies a considerably wide range of the firstquadrant of the (a*, b*) plane when various skin colors are considered;however, since the end portions of the range are set so that thecorrection intensity W decreases gradually, the influence to colorsdeviated from the skin color is relatively small, whereby no turn-backoccurs in the (a*, b*) plane and continuous gradation can be obtained.

Furthermore, when the skin colors in the shade of a person areconsidered, a relatively wide range is occupied on the luminance axis.However, in regions close to a highlight portion and in dark regions,colors high in saturation are not present originally, whereby the wideregion determined in the (a*, b*) plane shown in FIG. 2( a) becomesimproper. Since it is not necessary to correct up to very dark skincolors from the viewpoint of the beauty of an image, the functiongeneration means 210C having the characteristic of FIG. 2( d) iseffective in reducing the side effects of skin color correction.

Herein, as an example, how the correction intensity W is determined forthe color indicated by Δ is described using FIG. 2. Since the colorindicated by Δ is fairly bright and a skin color close to yellow and aconsiderably dark color, the correction intensity WL in the luminancedirection has the smallest value, and this becomes the correctionintensity W, resulting in relatively weak correction. Since thecorrection intensity W is determined in consideration of not only thechromaticity signals (a*, b*) but also the luminance signal L asdescribed above, the side effects generated when a very dark skin coloris corrected can be reduced.

Next, the operation of the correction means 300A will be described.

In this embodiment, the luminance signal L* is not corrected, but onlythe chromaticity signals (a*, b*) are corrected. Since the luminancesignal is apt to be conspicuous in the disturbance in gradationvisually, the change in color is apt to directly lead to side effectswherein false contours and unnatural gradation are caused owing to thedisturbance in gradation; if the luminance of the skin color portion isdesired to be changed, it can be changed naturally using knowntechnologies, such as gradation correction and gamma correction, otherthan the memory color correction. In a similar method, it is of coursepossible to carry out moderate correction for luminance in a rangewherein the side effects can be ignored.

The correction means 300A in accordance with this embodiment carries outinternal division operation for the chromaticity signals (a*, b*) andthe target chromaticity values (a0, b0*) using the correction intensityW according to the following expressions.(a1*)=(1−W)(a*)+W(a0*)  (Expression 1)(b1*)=(1−W)(b*)+W(b0*)  (Expression 2)

Hence, when W=0, the input chromaticity signals (a*, b*) are directlyoutput, and when W=1, the target chromaticity values (a0*, b0*) areoutput.

Furthermore, it is not always necessary that the (a*, b*) values for thelargest value of the correction intensity W coincide with the targetcolor (a0*, b0*) of the skin color.

Still further, by setting the maximum value of the correction intensityW on each axis at 1 or less as shown in FIG. 2, colors close to thetarget color are pulled in, but they do not become the same color,whereby the natural changes in saturation and hue remain and thegradation is maintained.

The correction degree K set using the correction degree setting means600 is set according to the instruction of a user via the user interfaceof the controller of a printer not shown. For example, in the case of animage including no persons or in the case that faithful colorreproduction is desired without carrying out memory color correction, avalue close to 0 is set; in other cases, a value close to 1 is set. Themultiplication means 500 operates to adjust the correction intensity Woutput from the intensity determination means 200A in proportion to theabove-mentioned correction degree K. For example, the multiplicationmeans 500 adjusts the correction intensity W to the product of theabove-mentioned correction degree K and the correction intensity Woutput from the intensity determination means 200A. Then, using thecorrection intensity W whose value has been adjusted, theabove-mentioned internal division operation is carried out at thecorrection means 300A. For example, when the user sets the correctiondegree K at 0, memory color correction becomes completely inoperative.Furthermore, when the user sets the correction degree K at 1, sufficientmemory color correction is carried out.

In this embodiment, the memory color correction of skin color is takenas an example and described; however, the embodiment can also be usedfor the correction of other colors as a matter of course.

Furthermore, in this embodiment, (L*, a*, b*) are used as luminance andchromaticity signals; however, other than these, numerous luminancechromaticity color spaces, such as (L*, u*, v*), (Y, Cb, Cr), (Y, R-Y,B-Y) and (Y. U, V), can be used, whereby color spaces that can benarrowed easily according to the kinds of memory colors can be used.

Moreover, the correction means 300A is configured to correct onlychromaticity signals; however, it can also have a similar configurationfor the luminance signal.

Besides, the synthesizing means 220 comprises a minimum value detectioncircuit that outputs the minimum of the three signals; however, knownvarious nonlinear circuits having a similar effect, such as thearithmetic product of the three correction intensities, for example, canbe used.

Still further, the correction degree setting means 600 can carry outsetting by various automatic setting other than manual setting conductedby the above-mentioned user. With respect to the multiplication means500, a means capable of changing the magnitude of the correctionintensity W depending on the magnitude of the correction degree K, notcarrying out multiplication, may also be used. For example, a minimumvalue detection circuit or the like can also be used.

The intensity determination means 200A and the correction means 300A inaccordance with this embodiment are examples of color conversion meansin accordance with the present invention; the correction degree settingmeans 600, the intensity determination means 200A, the multiplicationmeans 500 and the correction means 300A in accordance with thisembodiment are examples of the color conversion means in accordance withthe present invention; the function generation means 210A in accordancewith this embodiment is an example of a second function generation meansin accordance with the present invention; the function generation means210B in accordance with this embodiment is an example of a thirdfunction generation means in accordance with the present invention; thefunction generation means 210C in accordance with this embodiment is anexample of a first function generation means in accordance with thepresent invention; the correction intensity Wa in accordance with thisembodiment is an example of a candidate of a second correction intensityin accordance with the present invention; the correction intensity Wb inaccordance with this embodiment is an example of a candidate of a thirdcorrection intensity in accordance with the present invention; thecorrection intensity WL in accordance with this embodiment is an exampleof a first correction intensity in accordance with the presentinvention; and the correction intensity W in accordance with thisembodiment is an example of a correction intensity in accordance withthe present invention.

Embodiment 2

FIG. 3 is a block diagram showing a schematic configuration of an imageprocessing apparatus in accordance with Embodiment 2 of the presentinvention. This embodiment has uses similar to those of theabove-mentioned Embodiment 1, and is configured as a unit of carryingout the memory color correction of skin color and installed inside acolor printer. Hence, a card reader, a JPEG development processor, apage memory, a print engine, etc., not shown, other than the devicesshown in this block diagram, are present. In addition, in thisembodiment, input and output pixel signals are (R, G, B) signals, andluminance chromaticity signals are (L*, a*, b*).

Numeral 100B designates a memory color correction means, numeral 700designates a luminance chromaticity conversion means, numeral 710designates a luminance chromaticity inverse conversion means, andnumeral 600 designates a correction degree setting means; the samecomponents as those in accordance with Embodiment 1 are designated usingthe same reference numerals, and their detailed descriptions areomitted.

In addition, the memory color correction means 100B comprises anintensity determination means 200B of determining correction intensity Waccording to (L*, a*, b*), a target color setting means 400A of settingtarget chromaticity (a0*, b0*) for memory color correction, amultiplication means 500 of multiplying correction intensity W bycorrection degree K, and a correction means 300A of bringing thechromaticity signals (a*, b*) output from the luminance chromaticityconversion means 700 to the chromaticity values (a0*, b0*) set using thetarget color setting means 400A depending on the output of themultiplication means 500.

Furthermore, the intensity determination means 200B comprises atwo-dimensional function generation means 211, a function generationmeans 210C and a synthesizing means 221.

Regarding the image processing apparatus configured as described abovein accordance with Embodiment 2, its operation will be described below.

With respect to the luminance signal L* converted using the luminancechromaticity conversion means 700, correction intensity WL is outputfrom the function generation means 210C formed of an LUT, and withrespect to the chromaticity signals (a*, b*), correction intensity Wc isoutput from the two-dimensional function generation means 211. Thesynthesizing means 221 carries out operation of outputting the minimumvalue of WL and Wc.

The correction means 300A and the correction degree setting means 600are similar to those in accordance with Embodiment 1 and theirdescriptions are omitted.

FIG. 4 is an explanatory view showing an example of the two-dimensionalfunction generation means 211 of generating the correction intensity Wcin the (a*, b*) plane. The ellipse drawn in a thick line and representedby region 2 in the figure indicates a skin color region, and smallerellipses indicate correction intensity Wc using contour lines. In otherwords, the region 2 is a region wherein the correction intensity Wc hasa positive value. The upper left graph one-dimensionally shows the crosssection of the ellipse sectioned in the longitudinal-axis direction ofthe ellipse. Mark ♦ in the figure indicates the target color (a0*, b0*).The rectangle drawn in a dotted line and represented by region 1 showsthe skin color region described in Embodiment 1 for the purpose ofcomparison.

As described above, from the statistical results of various human skincolors actually photographed, the two-dimensional function generationmeans 211 in accordance with Embodiment 2 is suited for narrowingvarious skin colors to a necessary and sufficient form. Furthermore, asa skin color becomes nearer to the end of the skin color regionindicated by the ellipse drawn in the thick line, the correctionintensity Wc becomes smaller gradually; hence, even if a color otherthan the skin color desired to be corrected is present inside thisregion, its influence is relatively small. Still further, no turn-backoccurs in the (a*, b*) plane, and continuous gradation can be obtained.In this embodiment, a shape obtained by horizontally cutting an inclinedelliptical cone at a predetermined height is obtained by calculation inadvance and stored in the two-dimensional LUT.

A supplementary description regarding the meaning of the turn-back inthe above-mentioned (a*, b*) plane is given herein. FIG. 18( a) is anexplanatory view of the turn-back in the case of one dimension whereinone output corresponds to one input, two inputs, or three inputs.Furthermore, FIG. 18( b) is an explanatory view of the turn-back in the(a*, b*) plane.

In the case of one dimension, in the range indicated by R of FIG. 18(a), multiple inputs corresponding to a certain output are present. Inother words, in the range indicated by R, it is understood that even ifthe input increases monotonically, the output increases monotonicallyand decreases once and then increases again. This kind of case is thecase wherein a turn-back occurs. Hence, the fact that a turn-back occursin the (a*, b*) plane means a state wherein in the case that when theinput is changed continuously from a certain color A to a certain colorB, the output changes from A′ to B′ as shown in FIG. 18( b), colorchange occurs first in the direction toward B′ in the range between A′to B′, but the direction changes once to the direction toward A′ at acertain color, and then color change occurs again in the directiontoward B′.

In this embodiment, the turn-back in the (a*, b*) plane as shown in FIG.18( b) does not occur, but continuous gradation can be obtained.

In the direction of luminance, a configuration wherein the functiongeneration means 210C having the characteristic shown in FIG. 2( d)identical to that of Embodiment 1 is used together is adopted, wherebythe skin color region actually desired to be corrected can be narrowednecessarily and sufficiently from a wide range from a dark portion to ahighlight portion, thereby being effective in reducing the side effectsof skin color correction.

In this embodiment, the memory color correction of skin color is takenas an example and described; however, the embodiment can also be usedfor correction of other colors as a matter of course.

Furthermore, (L*, a*, b*) are used as luminance and chromaticitysignals; however, other than these, numerous luminancechromaticity-based color spaces, such as (L*, u*, v*), (Y, Cb, Cr), (Y,R-Y, B-Y) and (Y, U, V), can be used, whereby color spaces that can benarrowed easily according to the kinds of memory colors can be used.

Still further, the two-dimensional function generation means has beendescribed using the function of an elliptical shape; however, a freeshape can be used actually depending on the distribution of a targetcolor, and as a function generating method, a method of usingmathematical expression calculation, other than the two-dimensional LUT,can also be used.

Moreover, the correction means 300A is configured to correct onlychromaticity signals; however, it can also have a similar configurationfor the luminance signals.

Besides, the synthesizing means 221 comprises a minimum value detectioncircuit that outputs the minimum of the two signals; however, knownvarious nonlinear circuits having a similar effect, such as anarithmetic product of the two correction intensities, for example, canbe used.

Still further, the correction degree setting means 600 can carry outsetting by various automatic setting other than manual setting conductedby the above-mentioned user. With respect to the multiplication means500, a means capable of changing the magnitude of the correctionintensity W depending on the magnitude of the correction degree K, notcarrying out multiplication, may also be used. For example, a minimumvalue detection circuit or the like can also be used. The details of thecorrection degree setting means 600 will be described later.

The intensity determination means 200B and the correction means 300A inaccordance with this embodiment are examples of the color conversionmeans in accordance with the present invention; the correction degreesetting means 600, the intensity determination means 200B and thecorrection means 300A in accordance with this embodiment are examples ofthe color conversion means in accordance with the present invention; thefunction generation means 210C in accordance with this embodiment is anexample of the first function generation means in accordance with thepresent invention; the correction intensity WL in accordance with thisembodiment is an example of the first correction intensity in accordancewith the present invention; the correction intensity Wc in accordancewith this embodiment is an example of the second correction intensity inaccordance with the present invention; and the correction intensity W inaccordance with this embodiment is an example of the correctionintensity in accordance with the present invention.

Embodiment 3

FIG. 5 is a block diagram showing a schematic configuration of an imageprocessing apparatus in accordance with Embodiment 3 of the presentinvention. This embodiment has uses similar to those of theabove-mentioned embodiments, and is configured as a unit of carrying outthe memory color correction of sky blue. A card reader, a JPEGdevelopment processor, a page memory, a print engine, etc., not shown,other than the devices shown in this block diagram, are present. Inaddition, in this embodiment, input and output pixel signals are (R, G,B) signals, and luminance chromaticity signals are (L*, a*, b*).

Numeral 100C designates a memory color correction means, numeral 700designates a luminance chromaticity conversion means, numeral 710designates a luminance chromaticity inverse conversion means, andnumeral 600 designates a correction degree setting means; the samecomponents as those in accordance with the above-mentioned embodimentsare designated using the same reference numerals, and their detaileddescriptions are omitted.

In addition, the memory color correction means 100C comprises anintensity determination means 200C of determining correction intensity Waccording to (L*, a*, b*), a target color setting means 400A of settingtarget chromaticity (a0*, b0*) for sky blue, and a correction means 300Aof bringing the signals to the chromaticity values (a0*, b0*) set usingthe target color setting means 400A depending on the correctionintensity W.

Next, the configuration of the intensity determination means 200C inaccordance with this embodiment, different from the configuration inaccordance with the above-mentioned embodiments, will be described.

Numeral 230 designates a polar coordinate conversion means of convertingthe chromaticity signals (a*, b*) into hue and sat represented in thepolar coordinate system, numeral 210D designates a function generationmeans of outputting correction intensity Wh on the hue axis, 210Edesignates a function generation means of outputting correctionintensity Ws on the saturation axis, 210C designates a functiongeneration means of outputting correction intensity WL on the luminanceaxis, and numeral 222 designates a synthesizing means of synthesizingthree correction intensities.

Regarding the image processing apparatus configured as described abovein accordance with Embodiment 3, its operation will be described below.

With respect to the luminance signal L* converted using the luminancechromaticity conversion means 700, correction intensity WL is outputusing the function generation means 210C formed of an LUT, and thechromaticity signals (a*, b*) are converted using the polar coordinateconversion means 230 such that hue is represented by angle and sat isrepresented by length. Hue is converted into correction intensity Wh inthe hue direction using the function generation means 210D, and sat isconverted into a correction intensity Ws in the saturation directionusing the function generation means 210E.

FIGS. 6( d), 6(b) and 6(c) show examples of the LUTs constitutingfunction generation means for luminance L*, hue and sat, respectively.The positive value ranges of the correction intensities WL, Wh and Wsdetermine the sky blue regions in respective axial directions. FIG. 6(a) shows the sky blue region determined using the three-dimensionalcorrection intensity W synthesized using the synthesizing means 222 inthe (a*, b*) plane, the thick line indicates the sky blue region, andthe correction intensity W is shown using thin contour lines. Inaddition, Mark ♦ indicates a target color (a0*, b0*).

The size of the sky blue region is determined on the basis of thestatistics of extracted colors obtained by extracting sky portions fromvarious landscape images taken actually. As a result of statistics, insky images, colors with a wide range of hue, exceeding 90 degrees inhue, from a color close to cyan to a color close to violet, are present,and colors with a wide range of saturation, from a color close to anachromatic color of an obscured sky to a bright color of a clear sky ina southern country are present. Because of this wide range, the settingof the correction intensity in the chromaticity plate in the orthogonalcoordinate system and the setting in the polar coordinate system aredifferent significantly; hence, it is almost impossible to carry out thesetting in the orthogonal coordinate system, and it is found that thesetting should preferably be carried out in the polar coordinate system.Hence, the end portion of the fan-shaped range is set so that thecorrection intensity decreases gradually, whereby the wide range of skyblue can be covered properly, and natural gradation with no turn-backcan be attained.

In addition, the color of a very bright sky is close to white and low insaturation, and it is not necessary to correct up to very dark sky bluefrom the viewpoint of beauty of an image, whereby the functiongeneration means 210C having the characteristic of FIG. 6( d) iseffective in reducing the side effects of the memory color correction ofsky blue. It is actually confirmed that the influence on objects of darkblue, not sky blue, is relieved significantly by the effect of thefunction generation means 210C.

In this embodiment, as in the above-mentioned embodiments, the luminancesignal L* is not corrected, but only the chromaticity signals (a*, b*)are corrected. Since the luminance signal is apt to be conspicuous inthe disturbance in gradation visually, the change in color is apt todirectly lead to side effects wherein false contours and unnaturalgradation are caused by the disturbance in gradation; if the luminanceof the sky blue portion is desired to be changed, it can be changednaturally using known technologies, such as gradation correction andgamma correction, other than the memory color correction. It is ofcourse possible to carry out moderate correction for luminance in arange wherein the side effects can be ignored.

In this embodiment, the memory color correction of sky blue is taken asan example and described; however, the embodiment can be used for thecorrection of other colors as a matter of course. For example, the greenof plants, such as trees and grass, has a wide range in hue, as in skyblue, and also has a wide range in saturation. By carrying out thesetting of the correction intensity for the green of plants, such astrees and grass, using the polar coordinate system, as in thisembodiment, memory color correction can be carried out while the sideeffects are minimized.

Furthermore, (L*, a*, b*) are used as luminance and chromaticitysignals; however, other than these, numerous luminance chromaticitycolor spaces, such as (L*, u*, v*), (Y, Cb, Cr), (Y, R-Y, B-Y) and (Y,U, V), can be used, whereby color spaces that can be narrowed easilyaccording to the kinds of memory colors can be used.

Moreover, the correction means 300A is configured to correct onlychromaticity signals; however, it can also have a similar configurationfor the luminance signals.

Besides, the synthesizing means 222 comprises a minimum value detectioncircuit that outputs the minimum of the two signals; however, knownvarious nonlinear circuits having a similar effect, such as anarithmetic product of the two correction intensities, for example, canbe used.

Still further, the correction degree setting means 600 can carry outsetting by various automatic setting other than manual setting conductedby the above-mentioned user. With respect to the multiplication means500, a means capable of changing the magnitude of the correctionintensity W depending on the magnitude of the correction degree K, notcarrying out multiplication, may also be used. For example, a minimumvalue detection circuit or the like can also be used. The details of thecorrection degree setting means 600 will be described later.

The intensity determination means 200C and the correction means 300A inaccordance with this embodiment are examples of the color conversionmeans in accordance with the present invention; the correction degreesetting means 600, the intensity determination means 200C and thecorrection means 300A in accordance with this embodiment are examples ofthe color conversion means in accordance with the present invention; thefunction generation means 210C in accordance with this embodiment is anexample of the first function generation means in accordance with thepresent invention; the function generation means 210D in accordance withthis embodiment is an example of the second function generation means inaccordance with the present invention; the function generation means210E in accordance with this embodiment is an example of the thirdfunction generation means in accordance with the present invention; thecorrection intensity WL in accordance with this embodiment is an exampleof a candidate of the first correction intensity in accordance with thepresent invention; the correction intensity Wh in accordance with thisembodiment is an example of a candidate of the second correctionintensity in accordance with the present invention; the correctionintensity Ws in accordance with this embodiment is an example of thethird correction intensity in accordance with the present invention; andthe correction intensity W in accordance with this embodiment is anexample of the correction intensity in accordance with the presentinvention.

Embodiment 4

FIG. 7 is a block diagram showing a schematic configuration of an imageprocessing apparatus in accordance with Embodiment 4 of the presentinvention. This embodiment is configured as a unit of carrying out thememory color correction of sky blue, as in Embodiment 3.

Numeral 100D designates a memory color correction means, numeral 700designates a luminance chromaticity conversion means, and numeral 710designates a luminance chromaticity inverse conversion means; the samecomponents as those in accordance with the above-mentioned embodimentsare designated using the same reference numerals, and their detaileddescriptions are omitted.

In addition, the memory color correction means 100D comprises thefollowing.

Numeral 200C designates an intensity determination means, numeral 300Bdesignates a correction means of carrying out correction in the polarcoordinate system, numeral 400B designates a target color setting meansof setting a target color, that is, target hue hue0 and targetsaturation sat0, in the polar coordinate system.

In addition, the correction means 300B comprises the following.

Numeral 320 designates a polar coordinate conversion means, 310A and310B designate internal division means of internally dividing the hueand sat output from the polar coordinate conversion means 320, andnumeral 330 designates an orthogonal coordinate conversion means ofcarrying out inverse conversion from the polar coordinate system to theorthogonal coordinate system.

Regarding the image processing apparatus configured as described abovein accordance with Embodiment 4, its operation will be described below.

The intensity determination means 200C similar to that of Embodiment 3first outputs the correction intensity W of a sky blue region on thebasis of the chromaticity signals (a*, b*) and the luminance signal L*output from the luminance chromaticity conversion means 700. At the sametime, the chromaticity signals (a*, b*) are converted into hue and satusing the polar coordinate conversion means 230. The internal divisionmeans 310A internally divides the hue signal hue and the hue signal hue0of the target color using the correction intensity W and outputs ashue1. In a similar way, the internal division means 310B internallydivides the saturation signal sat and the saturation signal sat0 of thetarget color using the correction intensity W and outputs as sat1.Together with hue1 and sat1, hue and sat, not corrected, are output whenW is 0; when W is 1, hue0 and sat0, representing the target sky blue,are output. The hue1 and sat1 subjected to memory color correction arereturned to the chromaticity signals (a1*, b1*) subjected to memorycolor correction using orthogonal coordinate conversion means 330.

As described in the above-mentioned Embodiment 3, the region of sky bluehas a very wide range. Hence, in Embodiment 3, the correction intensityis obtained using the hue and saturation axes obtained when chromaticityvalues are subjected to polar coordinate conversion in Embodiment 3;however, in a similar way, the correction means 300B is also required tocarry out natural correction of sky blue having the wide range.

FIG. 8 is an explanatory view showing the effect of the correction means300B in accordance with this embodiment. Mark ◯ indicates a targetcolor, and mark Δ indicates an input color. A case wherein correctionintensity w=0.5 is input is considered as an example. If the correctionmeans 300A in accordance with the above-mentioned embodiments is used,an internal division of 50% in the orthogonal coordinate system isobtained, and the color indicated by mark ⋄ is output. On the otherhand, in the case of the correction means 300B, the hue becomes 50% interms of angle, and the saturation is internally divided into 50% interms of distance from the origin, whereby the color indicated by mark ♦is output. However, in the results of the correction means 300A, thecorrection amount of hue becomes insufficient, and the saturation alwaysbecomes fairly low. This trend does not cause much difference in thecorrection within a narrow color region, such as skin color correction;however, the trend becomes conspicuous when correction is carried outfor wide chromaticity ranges, such as the regions of the sky blue of thesky and the green of plants, such as trees and grass, whereby thisembodiment leads to preferable results.

In this embodiment, the luminance signal L* is not corrected either;however, moderate correction can also be carried out for luminance usinga similar method in a range of not causing side effects.

In this embodiment, the memory color correction of sky blue is taken asan example and described; however, the embodiment can also be used forcorrection of other colors as a matter of course. In particular, asdescribed in Embodiment 3, regarding the memory color correction of thegreen of plants, such as trees and grass, excellent results can also beobtained as in the case of sky blue.

Furthermore, (L*, a*, b*) are used as luminance and chromaticitysignals; however, other than these, numerous luminance chromaticitycolor spaces, such as (L*, u*, v*), (Y, Cb, Cr), (Y, R-Y, B-Y) and (Y,U, V), can be used, whereby color spaces that can be narrowed easilyaccording to the kinds of memory colors can be used.

Still further, in this embodiment, the adjustment of the correctiondegree K using the correction degree setting means is omitted; however,the adjustment can be added using a method similar to that of theabove-mentioned embodiment as a matter of course. The details of thecorrection degree setting means 600 will be described later.

The intensity determination means 200C and the correction means 300B inaccordance with this embodiment are examples of the color conversionmeans in accordance with the present invention; the correction degreesetting means 600, the intensity determination means 200C, themultiplication means 500 and the correction means 300B in accordancewith this embodiment are examples of the color conversion means inaccordance with the present invention; and the polar coordinateconversion means 320 in accordance with this embodiment is an example ofa second polar coordinate conversion means in accordance with thepresent invention.

Embodiment 5

FIG. 9 is a block diagram showing a schematic configuration of an imageprocessing apparatus in accordance with Embodiment 5 of the presentinvention. This embodiment is configured as a unit of carrying out thememory color correction of sky blue, as in Embodiments 3 and 4.

Numeral 100E designates a memory color correction means, numeral 700designates a luminance chromaticity conversion means, and numeral 710designates a luminance chromaticity inverse conversion means; the samecomponents as those in accordance with the above-mentioned embodimentsare designated using the same reference numerals, and their detaileddescriptions are omitted.

In addition, the memory color correction means 100E comprises thefollowing.

Numeral 201C and 202C each designate an intensity determination means,numeral 300B designates a correction means of carrying out correction inthe polar coordinate system, numeral 400B designates a target colorsetting means of setting a target color, that is, target hue hue0 andtarget saturation sat0.

In addition, the correction means 300B comprises a polar coordinateconversion means 320, internal division means 310A and 310B and anorthogonal coordinate conversion means 330.

Next, the operation of this kind of embodiment will be described.

The image processing apparatus in accordance with Embodiment 5 ischaracterized in that it is equipped with two separate means, anintensity determination means 201C of determining correction intensityW1 for carrying out hue correction and an intensity determination means202C of determining correction intensity W2 for carrying out saturationcorrection using the correction means 300B. The intensity determinationmeans 201C and the intensity determination means 202C are the same inconfiguration as the intensity determination means 200C shown in FIG. 5,but are different in the contents of the LUTs of the function generationmeans 210C, 210D and 210E.

The memory color correction of sky blue operates so that the hue closeto cyan is rotated in the positive direction, and the hue close toviolet is rotated in the negative direction, whereby the sky blue ispulled to the hue of the target blue. In a similar way, the saturationof sky blue having too high saturation is lowered, and the saturation ofsky blue having too low saturation is raised, whereby the sky blue ispulled so as to have the saturation of the target color.

However, the color of an obscured sky and the color of the sky slightlyappearing from between thin clouds are very low in saturation and closeto an achromatic color. If colors having these chromaticity levels areincluded in the sky blue correction range, a side effect is caused, thatis, white and gray are raised in saturation and slightly colored in thedirections of cyan, blue and violet. This side effect is recognized ascolor cast and significantly degrades image quality. In addition, evenin the case of an object being white essentially, a slight white balanceerror in a camera is magnified extremely.

Hence, since it is usually difficult to include the above-mentioned skyblue being low in saturation within the memory color correction range,the above-mentioned saturation region is excluded from the correctionrange. In this case, the color of a cloudless sky is subjected tocorrection and is changed so as to have the target hue; however, thecolor of the sky slightly appearing from between the boundaries ofclouds remains in the original color; hence, the naturalness as an imageis impaired, the image becomes an artificial composite image, and theimage quality improving effect of the memory color correction isimpaired.

In this embodiment, two intensity determination means are provided, andthe correction of hue and the correction of saturation are madeindependent, whereby both the above-mentioned problems can be solved.

The intensity determination means 201C for hue correction sets thecorrection intensity W1 being used for carrying out correction in a widerange from the above-mentioned low saturation region to the highsaturation region, and the intensity determination means 202C ofsaturation correction sets the correction intensity W2 being used forexcluding the low saturation region from the target of correction. It iseffective to exclude the high saturation region from the target ofcorrection at the same time, from a viewpoint of not lowering thesaturation of bright sky blue.

FIG. 10( a) shows an example of the saturation-use function generationmeans 210E constituting the intensity determination means 201C, and FIG.10( b) shows an example of the saturation-use function generation means210E constituting the intensity determination means 202C. The range ofsaturation sat wherein the intensity has a positive value in thesaturation-use function generation means 210E of the intensitydetermination means 201C of generating intensity W1 for carrying out huecorrection is wider than that in the saturation-use function generationmeans 210E of the intensity determination means 202C of generatingintensity W2 for carrying out saturation correction.

As both the hue-use function generation means 210C and thesaturation-use function generation means 210E, those shown in FIGS. 6(b) and 6(d) are used. Their effects can be raised further by theirrespective independent optimization as a matter of course.

With this embodiment, only the hue correction is carried out for the skyblue close to gray and low in saturation, the above-mentioned problem,thereby being effective as the memory color correction of sky blue. Inaddition, since the saturation is not corrected, coloring is notenhanced, whereby slight coloring of gray owing to a white balance erroror the like is not emphasized. Hence, since a wide region can be used asthe target of the correction range, the hue at the boundary between acloud and the sky does not become unnatural, whereby very natural memorycolor correction of sky blue can be carried out.

In this embodiment, the luminance signal L* is not corrected either;however, moderate correction can also be carried out for luminance usinga similar method in a range of not causing side effects.

In this embodiment, the memory color correction of sky blue is taken asan example and described; however, the embodiment can also be used forcorrection of other colors as a matter of course. In particular, asdescribed in Embodiment 3, regarding the memory color correction of thegreen of plants, such as trees and grass, excellent results can also beobtained as in the case of sky blue.

Furthermore, (L*, a*, b*) are used as luminance and chromaticitysignals; however, other than these, numerous luminance chromaticitycolor spaces, such as (L*, u*, v*), (Y, Cb, Cr), (Y, R-Y, B-Y) and (Y,U, V), can be used, whereby color spaces that can be narrowed easilyaccording to the kinds of memory colors can be used.

Still further, in this embodiment, the adjustment of the correctiondegree K using the correction degree setting means is omitted; however,the adjustment can be added using a method similar to that of theabove-mentioned embodiment as a matter of course.

The intensity determination means 202C, the intensity determinationmeans 201C and the correction means 300B in accordance with thisembodiment are examples of the color conversion means in accordance withthe present invention; the correction intensity W1 in accordance withthis embodiment is an example of a hue correction intensity inaccordance with the present invention; the correction intensity W2 inaccordance with this embodiment is an example of a saturation correctionintensity in accordance with the present invention; the polar coordinateconversion means 320 in accordance with this embodiment is an example ofthe second polar coordinate conversion means in accordance with thepresent invention; the internal division operation means 310A inaccordance with this embodiment is an example of the hue correctionmeans in accordance with the present invention; and the internaldivision operation means 310B in accordance with this embodiment is anexample of the saturation correction means in accordance with thepresent invention.

Embodiment 6

FIG. 11 is a block diagram showing a schematic configuration of an imageprocessing apparatus in accordance with Embodiment 6 of the presentinvention. This embodiment is configured as a unit of carrying out thememory color correction of sky blue, as in Embodiments 3, 4 and 5.

In FIG. 11, numeral 800 designates a memory card in which photographedimages and photographic information obtained at the time ofphotographing are recorded, numeral 900 designates a memory in whichimages read out from the memory card 800 are stored, numeral 700designates a luminance chromaticity conversion means, numeral 600Adesignates a correction degree setting means, numeral 100F designates amemory color correction means, and numeral 710 designates a luminancechromaticity inverse conversion means; the same components as those inaccordance with the above-mentioned embodiments are designated using thesame reference numerals, and their detailed descriptions are omitted.

In addition, the correction degree setting means 600A comprises a skyimage identification means 610A of obtaining reliability TSa ofincluding the sky in an image according to an image signal, aphotographic information identification means 620A of obtainingreliability TSb of including the sky in an image according to thephotographic information, and a correction degree determination means630A of determining correction degree K according to the reliability TSaoutput from the sky image identification means 610A and the reliabilityTSb output from the photographic information identification means 620A.

Furthermore, the sky image identification means 610A comprises a regioninformation calculation means 611 of calculating a characteristic amountof each region obtained by dividing an image vertically andhorizontally, a sky region candidate detection means 612 of judgingwherein each region is a sky region candidate or not, and a sky regiondistribution judgment means 613 of obtaining the reliability TSa ofincluding the sky according to the distribution of the sky regioncandidates.

Regarding the image processing apparatus configured as described above,its operation will be described below.

Photographed image data recorded in the memory card 800 is divided intoan image signal and photographic information, and the image signal isrecorded in the memory 900, and the photographic information is input tothe photographic information identification means 620A.

The photographic information includes various conditions and the presetvalues of a camera during photographing, which are recorded in thememory card 800 using the camera together with the image signal duringphotographing of an image; for example, incidental information regardingphotographing conditions specified in Exif serving as an image fileformat standard for digital still cameras corresponds to this.

The photographic information identification means 620A judges thepossibility of including the sky in an object according to thephotographic information. At this time, the distance to the object, thelight source during photographing, photographic scene information andphotographing time are used as the photographic information. In the casethat only some of the above are recorded as the photographicinformation, identification is carried out according to only thephotographic information.

More specifically, recognition is made as to whether the distance to theobject is either one of macro view, near view, distant view and unknownview, and in the cases other than macro view, it is judged that there isa possibility that the sky may be included.

In addition, recognition is made as to whether the light source duringphotographing is either outdoor light or indoor light; in the case ofoutdoor light, it is judged that the sky may be included.

Regarding photographic scene information, recognition is made as towhether the scene is a night scene or not. In the cases other than anight scene, it is judged that there is a possibility that the sky maybe included.

Regarding photographing time, recognition is made as to whether the timeis either daytime or nighttime. The photographing time cannot be useddirectly for the judgment as to whether the sky is included or not;however, in the case of nighttime, it is judged that the sky is notincluded so that side effects on an image of the sky photographed duringnighttime is avoided in memory color correction.

In addition, in the judgment of the light source during photographing, afluorescent lamp, an incandescent lamp and the like are included as alight source that can be judged as indoor light; however, a certain typeof fluorescent lamp has a color temperature close to that of daylight;in this case, it is difficult to estimate the light source. On the otherhand, the incandescent lamp relatively significantly differs fromdaylight in terms of color temperature, and its estimation is easy. Inthe case that the light source during photographing is significantlydifferent from daylight in terms of color temperature as describedabove, there is a high possibility that the light source of a camera maybe estimated properly, and it can thus be judged that the possibility ofincluding the sky is significantly low.

On the basis of the possibility of including the sky obtained accordingto the respective photographic information, the reliability TSb ofincluding the sky in an image according to the final photographicinformation is obtained using the fuzzy inference. Examples of fuzzycontrol rules at this time are shown below.

Rule 1: IF distance to object=macro THEN TSb=small

Rule 2: IF distance to object=other than macro THEN TSb=slightly large

Rule 3: IF light source=indoor light, light source=incandescent lampTHEN TSb=small

Rule 4: IF light source=outdoor light THEN TSb=slightly large

Rule 5: IF photographic scene information=night scene THEN TSb=small

Rule 6: IF photographic scene information=other than night scene THENTSb=slightly large

Rule 7: IF photographing time=nighttime THEN TSb=small

Rule 8: IF photographing time=other than nighttime THEN TSb=slightlylarge

Although the fuzzy inference has been used to obtain the reliability TSbof including the sky in an image according to the photographicinformation, a means capable of changing the magnitude of thereliability TSb by reflecting multiple pieces of photographicinformation may be used. For example, the table of the reliability TSbfor the combination of all the photographic information may also beused.

In the above-mentioned descriptions, an example wherein the distance tothe object, the light source during photographing, photographic sceneinformation and photographing date and time are used as the photographicinformation has been shown; however, other than these, photographingsite, shutter speed and aperture value can also be used.

During photographing an image including the sky, the amount of light islarge, whereby the shutter speed becomes high and the aperture valuebecomes large. Hence, the brightness of an object is estimated accordingto the shutter speed and the aperture value; in the case that thebrightness is higher than a certain value, it can be judged that thereis a possibility that the sky may be included in the object. At thistime, the brightness to be judged according to the photographing timecan also be changed. The fact that the brightness to be judged accordingto the photographing time is changed means that the threshold value forjudging whether the photographing environment is bright or not ischanged. During daytime, there is a possibility that the photographingenvironment may be bright, and during nighttime, there is a possibilitythat the photographing environment may not be bright. Hence, forexample, during daytime, the threshold value for judging whether thephotographing environment is bright or not can be set higher, and duringnighttime, this threshold value can be set lower.

In addition, the photographing time is divided into morning time,daytime, evening time and nighttime, and the operation of the memorycolor correction may be switched respectively. The judgment of morningtime and evening time can be carried out by obtaining the sunrise timeand sunset time of a photographing date. Furthermore, the sunrise timeand sunset time can also be obtained regardless of district using theGPS information regarding the photographing site.

Furthermore, in the identification of the photographic information, theidentification may be carried out using all the above-mentionedphotographic information, or the identification may be carried out usingpart of the photographic information.

The region information calculation means 611 roughly divides an imagesignal output from the memory 900 into regions vertically andhorizontally according to the coordinates in the image, and calculatesregion information comprising the average luminance, average hue andaverage saturation for each region. At this time, the calculation iscarried out while the image signal inside the region is thinned out forhigh-speed processing.

The sky region candidate detection means 612 judges whether a sky regionis present in each region according to the region information, that is,the output signal of the region information calculation means 611. Morespecifically, average R value Rmean, average G value Gmean and average Bvalue Bmean are calculated in each region according to the averageluminance Lmean, average hue and average saturation. In this embodiment,in the sky region candidate detection, the detection is carried out in arange wider than the range of the color to be actually subjected tocolor correction using the memory color correction means 100F, and theprocessing is easy; because of these reasons, the sky region candidatesare judged by comparing Rmean, Gmean and Bmean. More specifically, skyregion candidate C is judged according to the next logical expressionfor each region using the threshold value Lth of a certain luminancelevel.C=(Bmean>Rmean)&&(Bmean>Gmean)&&(Lmean>Lth)  (Expression 3)

In Expression 3, && means logical AND operation. In other words, A&&B (Aand B are logical expressions) becomes 1 when both A and B are 1, andbecomes 0 when both of A and B are not 1 and when either one of A and Bis not 1. Hence, Expression 3 represents that C=1 when Bmean is largerthan Rmean, Rmean is larger than Gmean and Lmean is larger than Lth andthat C=0 in the other cases. Herein, C=1 represents that the region is asky region candidate, and C=0 represents that the region is not a skyregion candidate.

Furthermore, in the case that a portion being high in saturation,although being small in area, is present in an image, owing to itsinfluence, erroneous detection may occur during sky region candidatedetection in some cases. For prevention of this problem, this kind oferroneous detection can be reduced by calculating the average saturationafter the saturation is limited to a constant level or less.

In this embodiment, a simple method of using the magnitude relationshipof the average values (R, G, B) for sky region candidate detection isadopted; however, other than this, it may be possible to adopt a methodwherein the average (R, G, B) values are weighted and then compared or amethod wherein a function similar to the narrowing of the target colorregion in the above-mentioned embodiments is used. Furthermore,luminance chromaticity color spaces, such as (L*, a*, b*), (L*, u*, v*),(Y, Cb, Cr), (Y, R-Y, B-Y) and (Y, U, V), other than (R, G, B), can alsobe used.

For example, as the method wherein the average (R, G, B) values areweighted and then compared, when Rmean and Gmean are respectivelymultiplied by weight 1 and Bmean is multiplied by a weight of largerthan 1, and Expression 3 is applied to Rmean, Gmean and Bmean havingbeen weighted as described above, the range of the color region to bejudged as sky blue becomes wider. Conversely, when Rmean and Gmean arerespectively multiplied by weight 1 and Bmean is multiplied by a weightof smaller than 1, and Expression 3 is applied to Rmean, Gmean and Bmeanhaving been weighted as described above, the range of the color regionto be judged as sky blue becomes narrower. Hence, when the average (R,G, B) values are weighted and then compared, the degree of identifyingwhether a roughly divided region is the sky or not can be fine-adjustedby adjusting the weights, whereby the accuracy of identifying whetherthe roughly divided region is the sky or not can be raised by settingproper weights.

In addition, as a method wherein functions similar to those used for thenarrowing of the target color region in the above-mentioned embodiments,the following should only be used, for example. That is to say, thefunctions used in the above-mentioned embodiments are applied to theaverage luminance Lmean, average hue and average saturation in a roughlydivided region, respectively, to obtain the respective intensities ofthe average luminance Lmean, average hue and average saturation. Theminimum value of these intensities is used as the overall intensity ofthe average luminance Lmean, average hue and average saturation. In thecase that the overall intensity has a positive value, it is judged thatthe sky is included in the roughly divided region; in the case that thisoverall intensity is 0, it is judged that the sky is not included in theroughly divided region. Whether the roughly divided region includes thesky or not can also be identified by using this method.

The sky region distribution judgment means 613 calculates the product ofthe sky region candidate information output from the sky regioncandidate detection means 612 and a predetermined sky region judgmentmask for each region, and the reliability TSa of including the sky in animage according to the image information is obtained from the sumthereof.

In an image obtained by photographing a landscape, the sky is usuallypositioned in the upper portion of the image. Hence, a proper judgmentcan be made by excluding the lower portion of the image from the targetof processing at the time of sky region judgment. In addition, a camerais sometimes held vertically during photographing so that an image istaken an oblong image; even in this kind of case, judgment can becarried out properly by using the left and right portions of the imageas the targets for sky region judgment. FIG. 12( c) shows an example ofthe sky region judgment mask in which these are reflected. In thisexample, the sky region judgment mask is formed of binary values, andthe lower central portion of the image is excluded from the target forsky region judgment; however, for example, it may be possible to use aconfiguration wherein each region is weighted so that the upper portionof the image is weighted heavily and the lower portion is weightedlightly.

At this time, in the case that information as to whether the image is avertical image or a horizontal image is obtained as photographicinformation, the sky region judgment mask can also be changed accordingto the information.

In addition, the operation of the sky region candidate detection means612 can also be changed according to the judgment results from thephotographic information. For example, since the sky is not used as amain object usually, a sky region judgment mask of using regions otherthan the object region as the sky region judgment target can also beobtained by using information regarding the position and region of theobject in the photographic information.

FIG. 12( a) shows a color image to be input, and this case is anconceptual view of a landscape image wherein the sky is photographed inthe upper portion of the image and a lake is photographed in the lowerportion of the image. FIG. 12( b) shows the result obtained when theimage is divided into regions of three blocks in the vertical directionand four blocks in the horizontal direction and sky region candidatedetection is carried out. FIG. 12( c) shows a sky region judgment mask,and FIG. 12( d) shows the result obtained when this judgment mask isapplied to the result of FIG. 12( b). By virtue of sky region candidatedetection, the correction degree determination means 630A determines thefinal correction degree K as the product of the reliability TSa ofincluding the sky in the image according to the image signal output fromthe sky image identification means 610A and the reliability TSb ofincluding the sky in the image according to the photographic informationoutput from the photographic information identification means 620A.

In the case that no photographic information has been recorded, thephotographic information identification means 620A does not output thereliability TSb, and the correction degree determination meansdetermines the correction degree K by using only the reliability TSa.

The luminance chromaticity conversion means 700 converts the imagesignal output from the memory into luminance chromaticity signals. Thememory color correction means 100F carries out memory color correctionfor the luminance chromaticity signals output from the luminancechromaticity conversion means 700 depending on the correction degree Koutput from the correction degree determination means 630A.

Hence, even an image being difficult in the judgment as to whether thesky is included or not when either the image or the photographicinformation is used independently can be judged with high reliability;whereby it is possible to reduce a side effect of carrying out thememory color correction of sky blue for an image not including the sky.

In addition, the correction degree determination means 630A may usecontinuous values as the correction degree K, as in this embodiment, ormay turn on/off memory color correction by adopting binarization using athreshold value. In the case of a means capable of changing themagnitude of the correction degree K depending on the magnitude of thereliabilities TSa and Tsb, multiplication may not be used.

Furthermore, the correction degree K is used for memory color correctionin this embodiment; however, other than this, it can also be used forwhite balance adjustment and gradation correction. In this case, itbecomes possible that proper effects are obtained by changinginformation derived from the photographic information and imagedepending on the contents of image processing to be carried out.

In this embodiment, a configuration in the case that sky blue iscorrected is shown; however, correction of other colors can also becarried out by properly configuring the image identification means andthe photographic identification means. This embodiment can be appliedto, for example, a case of correcting the green of plants, such as treesand grass. Furthermore, multiple colors in one image can also becorrected by using a configuration having multiple correction degreesetting means and multiple memory color correction means.

The correction degree setting means 600A and the memory color correctionmeans 100F in accordance with this embodiment are examples of the colorconversion means in accordance with the present invention; and the skyimage identification means 610A in accordance with this embodiment is anexample of the image identification means in accordance with the presentinvention.

Embodiment 7

FIG. 13 is a block diagram showing a schematic configuration of an imageprocessing apparatus in accordance with Embodiment 7 of the presentinvention. This embodiment is configured as a unit of carrying out thememory color correction of skin color, as in the above-mentionedEmbodiments 1 and 2.

In FIG. 13, numeral 800 designates a memory card in which photographedimages and photographic information obtained at the time ofphotographing are recorded, numeral 900 designates a memory in whichimages read out from the memory card 800 are stored, numeral 700designates a luminance chromaticity conversion means, numeral 600Bdesignates a correction degree setting means, numeral 100G designates amemory color correction means, and numeral 710 designates a luminancechromaticity inverse conversion means; the same components as those inaccordance with the above-mentioned embodiments are designated using thesame reference numerals, and their detailed descriptions are omitted.

In addition, the correction degree setting means 600B comprises a personimage identification means 610B of obtaining reliability TPa ofincluding a person in an image according to an image signal, aphotographic information identification means 620B of obtainingreliability TPb of including a person in an image according tophotographic information, and a correction degree determinationmeans630B of determining correction degree K according to thereliability TPa output from the person image identification means 610Band the reliability TPb output from the photographic informationidentification means 620B.

Next, the operation of this embodiment will be described.

Photographed image data recorded in the memory card 800 is divided intoan image signal and photographic information, and the image signal isrecorded in the memory 900, and the photographic information is input tothe photographic information identification means 620B.

The photographic information includes various conditions and the presetvalues of a camera during photographing, which are recorded in thememory card 800 using the camera together with the image signal duringphotographing of an image; for example, incidental information regardingphotographing conditions specified in Exif serving as an image fileformat standard for digital still cameras corresponds to this.

The photographic information identification means 620B judges thepossibility of including a person in an object according to thephotographic information. At this time, photographic scene informationand the distance to the object are used as the photographic information.

More specifically, in the case that the photographic scene informationis a person, it is judged that there is a high possibility that a personmay be included in an object.

In addition, in the case that the distance to an object is judged asmacro photographing or distant view, it is judged that there is a lowpossibility that a person may be included in the object as an object.This is because in macro photographing, a small object is photographed,and the object is rarely a person, and because even if a person isphotographed in distant view, its rate in the image is small, and it isestimated that the person is not a main object.

The reliability TPb of including a person in an image according to finalphotographic information is obtained on the basis of the fuzzy inferenceas in the above-mentioned Embodiment 6 since there is a possibility thata person may be included in an object obtained from respectivephotographic information.

Examples of using photographic scene information and the distance to anobject as the photographic information are provided in theabove-mentioned descriptions; however, other than these, informationregarding flash light emission can also be used.

More specifically, in the case of flash light emission, when its returnis not detected or when the luminance at the central portion in an imageis not relatively high, it is estimated that the object is located at adistance that the flash light does not reach. In this case, it is judgedthat there is a low possibility that a person may be included in theobject, as in the case that the distance to the above-mentioned objectis judged as distant view.

In addition, in the identification of the photographic information, theidentification may be carried out using all the above-mentionedphotographic information, or the identification may be carried usingpart of the photographic information.

The person image identification means 610B obtains the reliability TPaof including a person in an object according to an input image signal.For this purpose, a method wherein an image is divided into multipleregions and the judgment as to whether the color in each region is skincolor or not can be adopted, as in Embodiment 6, or various known meansof making judgment on the basis of the distribution of colors includedin an image and the like can be used.

At this time, the target regions of an image subjected to personrecognition can be set according to the information indicating theposition and region of an object and the information of the distance tothe object in the photographic information.

The correction degree determination means 630B determines the finalcorrection degree K as the product of the reliability TPa of including aperson in the image according to the image information output from theperson image identification means and the reliability TPb of including aperson in the image according to the photographic information outputfrom the photographic information identification means 620B.

In the case that no photographic information has been recorded, thephotographic information identification means 620B does not output thereliability TPb, and the correction degree determination meansdetermines the correction degree K by using only the reliability TPa.

As in the above-mentioned Embodiment 6, in the correction degreedetermination means 630B, the correction degree K may be binarized usinga threshold value, or a means other than multiplication may also beused.

The luminance chromaticity conversion means 700 converts the imagesignal output from the memory into luminance chromaticity signals. Thememory color correction means 100G carries out memory color correctionfor the luminance chromaticity signals output from the luminancechromaticity conversion means 700 depending on the correction degree Koutput from the correction degree determination means 630B.

Furthermore, the correction degree K is used for memory color correctionin this embodiment; however, other than this, it can also be used forwhite balance adjustment and gradation correction. In this case, itbecomes possible that proper effects are obtained by changinginformation derived from the photographic information and imagedepending on the contents of image processing to be carried out.

In this embodiment, a configuration in the case that human skin color iscorrected is shown; however, correction of other colors can also becarried out by properly configuring the image identification means andthe photographic identification means.

Furthermore, multiple colors in one image can also be corrected by usinga configuration having multiple correction degree setting means andmultiple memory color correction means.

The correction degree setting means 600B and the memory color correctionmeans 100G in accordance with this embodiment are examples of the colorconversion means in accordance with the present invention; and theperson image identification means 610B in accordance with thisembodiment is an example of the image identification means in accordancewith the present invention.

The contents described in the above-mentioned embodiments are notlimited to hardware mounting but can be configured by softwareprocessing as a matter of course. In addition, the software processingis not limited to only real-time processing; for example, aconfiguration wherein the results obtained by preprocessing inaccordance with the above-mentioned embodiments are stored in athree-dimensional look-up table (3DLUT) in which R, G and B are referredto as addresses and the 3DLUT is referred to during real-timeprocessing, such as printing, is possible as a matter of course. Inaddition, image processing results including memory color correction canbe obtained without enlarging the scale of hardware by storing theresults obtained when the memory color correction described in thisembodiment is carried out together in the 3DLUT being used for otherpurposes, such as color correction for printing. Furthermore,conformation to the correction degree being given in real time can beattained by internally dividing the respective reference results of anLUT including memory color correction and an LUT not including memorycolor correction by the correction degree.

Embodiment 8

FIGS. 14 to 17 are configuration diagrams of devices incorporating animage processing apparatus in accordance with this embodiment. InEmbodiment 8, application examples in which the image processingapparatuses described in the above-mentioned respective embodiments areincorporated in various devices will be described. The componentsdescribed in the above-mentioned respective embodiments are designatedusing the same numerals, and their descriptions are omitted.

FIG. 14 shows a printer 1001, FIG. 15 shows a television receiver (orprojector) 1010, FIG. 16 shows a video movie camera (or digital camera)1020, and FIG. 17 shows a portable telephone 1030. In these devices, theimage processing apparatuses described in the above-mentioned respectiveembodiments are incorporated. These devices will be described below.

First, the printer 1001 shown in FIG. 14 will be described.

The printer 1001 is an apparatus of printing input image datatransmitted from a personal computer (hereinafter referred to as PC)1002 on printing media, such as paper media.

The printer 1001 comprises a memory card 800, a memory 900, an imageprocessing apparatus 1000, a PC I/F 1003, a selector 1004, a colorconversion means 1006 and a printer head controller 1007.

The memory card 800 and the memory 900 have been described in theabove-mentioned embodiments.

In addition, the image processing apparatus 1000 is the image processingapparatus described in either one of the above-mentioned embodiments.

The PC I/F 1003 is an interface through which commands and data, such asimage signals, are transmitted between the printer driver, not shown, ofthe PC 1002 and the printer 1001.

The selector 1004 is a means of carrying out switching as to whetherimage data is input from the memory card 800 or image data is input fromthe PC 1002 via the PC I/F 1003.

The color conversion means 1006 is a means of converting output imagesignals serving as color signals, such as RGB, subjected to memory colorcorrection using the image processing apparatus 1000 into CMY signalsserving as print data. Herein, C, M and Y are cyan, magenta and yellow,corresponding to the three primary colors in the printer.

The printer head controller 1007 is a means of controlling the printerhead, not shown, of the printer 1001.

Next, the operation of this kind of printer 1001 will be described.

When image data is transmitted from the PC 1002, the PC I/F 1003receives the transmitted image data and outputs the data to the selector1004.

The selector 1004 receives the image data transmitted from the PC I/F1003 and stores the data in the memory 900. In addition, the selector1004 outputs various pieces of photographic information stored in theheader of the image data, for example. As the various pieces ofphotographic information, the various pieces of photographic informationdescribed in the header portion of an image file created using thedigital camera are used. In addition, in the case that printing iscarried out from the PC 1002, the setting (photo, CG, graph, etc.) ofthe printer driver of the PC 1002 is also used as photographicinformation. This setting of the printer driver is also output to theimage processing apparatus 1000. The image processing apparatus 1000obtains a correction degree by also using this kind of information otherthan pixel signals.

The image processing apparatus 1000 reads an input image signal from thememory 900 and carries out memory color conversion, described in theabove-mentioned embodiments, for the input image signal by also usingthe photographic information output from the selector 1004. When theimage processing apparatus 1000 carries out memory color conversion, thecorrection degree described in the above-mentioned embodiments can bedetermined by also using the setting information of the printer driver.For example, in the case that the setting of the printer driver isphoto, the correction degree obtained in the above-mentioned embodimentsis directly used, and in the case of CG or graph, the correction degreeis set at 0 or at a smallest value.

The image processing apparatus 1000 outputs an image signal subjected tomemory color conversion to the color conversion means 1006 as an outputimage signal.

The color conversion means 1006 converts the output image signal outputfrom the image processing apparatus 1000 and serving as color signals,such as RGB, into CMY signals serving as print data, and the imagesignal converted into the CMY signals is printed on printing media usingthe printer head, not shown, of the printer 1001 under the control ofthe printer head controller 1007.

Furthermore, in the case that the memory card 800 is mounted on theprinter 1001, the selector 1004 reads the image data stored in thememory card 800, stores the data in the memory 900 and outputs variousphotographic information described in the header portion of an imagefile created using the digital camera to the image processing apparatus1000. In the case that the memory card 800 is mounted on the printer1001, the setting information of the printer driver is not used. Exceptfor this, the subsequent operation is similar to that in the case thatimage data is transmitted from the PC 1002, and its detaileddescriptions are omitted.

As described above, by incorporating the image processing apparatus 1000in the printer 1001, it is possible to obtain print images subjected tooptimum automatic color adjustment according to memory colors.

The printer 1001 in accordance with this embodiment is an example of aprinter apparatus in accordance with the present invention, the PC I/F1003 in accordance with this embodiment is an example of an input meansin accordance with the present invention, and the printer headcontroller 1007 in accordance with this embodiment is an example of aprinting means in accordance with the present invention.

Next, the television receiver (or projector) 1010 shown in FIG. 15 willbe described. In the case of the television receiver, video datareceived using the receiving circuit of receiving broadcast waves isinput to a video I/F 1011. On the other hand, in the case of theprojector, image data transmitted from a PC is input to the video I/F1011. Although it has been described that the image data transmittedfrom the PC is input to the video I/F 1011 in the case of the projector,without being limited to this, the image data transmitted from anapparatus other than the PC, such as a video cassette recorder or a DVDplayer, may also be input to the video I/F 1011.

In addition, in the case of the television receiver, the video displayapparatus 1014 thereof comprises a cathode-ray tube, a liquid crystaldisplay apparatus, a plasma display apparatus or the like, and in thecase of the projector, it comprises a projection display apparatus orthe like.

Other components of the configuration shown in FIG. 15 are common to thetelevision receiver and the projector. Hence, in the subsequentdescription, the device shown in FIG. 15 is described as the televisionreceiver 1010; however, the subsequent description can also be appliedsimilarly to the projector.

The television receiver 1010 comprises an image processing apparatus1000, a memory card 800, a memory 900, the video I/F 1011, a selector1012, a display mode setting means 1013 and the video display apparatus1014.

The video I/F 1011 is an interface through which such image data asdescribed above is input.

The selector 1012 is a means of reading image data from the memory card800 or of reading image data from the video I/F 1011.

The display mode setting means 1013 is a means of setting the displaymode.

The video display apparatus 1014 is a means of displaying video images.

Next, the operation of this kind of television receiver 1010 will bedescribed.

The display mode setting means 1013 has an operation panel not shown,and the display mode is set by user operation on the operation panel. Inthe case of moving images, movie, natural, dynamic, etc. are set as thedisplay modes. Furthermore, in the case of still images, photo,presentation, etc. are set. The display mode setting means 1013 outputsthe display mode information having been set to the image processingapparatus 1000.

On the other hand, image data transmitted through broadcast waves from abroadcasting station is received using a receiving circuit, not shown,constituting the television receiver 1010 and demodulated. Thedemodulated image data is output to the video I/F 1011.

In the case that the image data is transmitted from the video I/F 1011,the selector 1012 receives the image data from the video I/F 1011 andstores the image data in the memory 900 once. In addition, the selector1012 outputs the photographic information held in the header of theimage data or the like to the image processing apparatus 1000.

The image processing apparatus 1000 carries out memory color correctionas in the case of the above-mentioned printer 1001. When the imageprocessing apparatus 1000 carries out memory color conversion, thecorrection degree described in the above-mentioned embodiments can bedetermined by also using the display mode information set using thedisplay mode setting means 1013. For example, in the case of dealingwith moving images, the image processing apparatus 1000 sets thecorrection degree at a small value when the display mode information ismovie, or sets the correction degree at a large value when the displaymode information is dynamic, or sets the correction degree at anintermediate value between the value for movie and the value for dynamicwhen the display mode information is natural. Furthermore, in the caseof dealing with still images, the image processing apparatus 1000 setsthe correction degree at a large value when the display mode informationis photo, or sets the correction degree at a small value when thedisplay mode information is presentation.

The image processing apparatus 1000 outputs an image signal subjected tomemory color correction to the video display apparatus 1014 as an outputimage signal. After receiving the output image signal, the video displayapparatus 1014 displays them on a liquid crystal display apparatus, forexample.

In addition, in the case that the memory card 800 is mounted on thetelevision receiver 1010, the selector 1012 reads image data stored inthe memory card 800, stores the data in the memory 900 and outputs thephotographic information stored in the header of the image data or thelike to the image processing apparatus 1000. Since the subsequentoperation is similar to that in the case that the image data istransmitted from the video I/F 1011, its detailed descriptions areomitted.

As described above, by incorporating the image processing apparatus 1000in the television receiver 1010, it is possible to display moving imagesand still images subjected to optimum automatic color adjustmentaccording to memory colors.

The television receiver 1010 in accordance with this embodiment is anexample of a television receiver in accordance with the presentinvention; the video display apparatus 1014 in accordance with thisembodiment is an example of a display means in accordance with thepresent invention; the projector 1010 in accordance with this embodimentis an example of a projector in accordance with the present invention;the video I/F 1011 in accordance with this embodiment is an example ofthe input means in accordance with the present invention; and the videodisplay apparatus 1014 in accordance with this embodiment is an exampleof a projection means in accordance with the present invention.

Next, the video movie camera (or digital camera) 1020 shown in FIG. 16will be described. In the case of the video movie camera, photographedmoving images are recorded on tape 1028, an optical disc 1029 or thelike; however, in some video movie cameras, photographed still imagesare recorded in the memory card 1027. On the other hand, in the case ofthe digital still camera, photographed still images are mainly recordedin the memory card 1027.

Other components of the configuration shown in FIG. 16 are common to thevideo movie camera and the digital camera. Hence, in the subsequentdescription, the apparatus shown in FIG. 16 is described as the videomovie camera 1020; however, the subsequent description can also beapplied similarly to the digital camera.

The video movie camera 1020 comprises an image processing apparatus1000, a CCD 1021, an A/D 1022, a memory 1023, a camera controller 1024,a photographing mode setting section 1025, an encoding means 1026, amemory card 1027, a tape 1028 and an optical disc 1029.

The CCD 1021 is a means of taking images and outputting analog imagesignals.

The A/D 1022 is a means of converting the analog image signals outputfrom the CCD 1021 into digital image signals.

The memory 1023 is a means of storing image data output from the A/D1022.

The camera controller 1024 is a means of controlling the camera sectionincluding the CCD 1021, photographic optical system, etc.

The photographing mode setting section 1025 is a means of settingphotographing modes.

The encoding means 1026 is a means of compressing and encoding imagedata subjected to memory color conversion using the image processingapparatus 1000.

The memory card 1027 is a means of mainly storing image data of stillimages.

The tape 1028 is a tape medium of mainly storing image data of movingimages.

The optical disc 1029 is an optical storage medium of mainly storingimage data of moving images.

Next, the operation of this kind of video movie camera 1020 will bedescribed.

The photographing mode setting means 1025 has a user interface notshown, and the photographing mode is set by user operation on theinterface. The photographing mode setting means 1025 outputs thephotographing mode information having been set to the image processingapparatus 1000.

On the other hand, the camera controller 1024 controls the camerasection including the CCD 1021, the photographic optical system, etc.when the photographing button is pressed.

The CCD 1021 takes images and outputs the images having been taken tothe A/D 1022 as electrical signals under the control of the cameracontroller 1024.

The A/D 1022 converts the analog image signals output from the CCD 1021into digital signals.

The image data output from the A/D 1022 is stored once in the memory1023.

The image processing apparatus 1000 reads the image data stored in thememory 1023 and carries out memory color conversion. When the imageprocessing apparatus 1000 carries out memory color conversion, thecorrection degree described in the above-mentioned embodiments can bedetermined by also using the photographing mode information having beenset using the photographing mode setting section 1025 or the like. Inother words, in the image processing apparatus 1000, the correctiondegree can be obtained as described in the above-mentioned embodimentsby also using information based on the user interface of the cameraitself, such as strobe light ON/OFF, and camera control information(focus, iris, etc.) as information other than pixel signals.

The image data subjected to memory color conversion using the imageprocessing apparatus 1000 is compressed and encoded using the encodingmeans 1026 and stored in the memory card 1027, the tape 1028 or theoptical disc 1029.

As described above, by incorporating the image processing apparatus 1000in the video movie camera 1020, it is possible to take images subjectedto optimum automatic color adjustment according to memory colors and tostore the images on a tape medium. In addition, by incorporating theimage processing apparatus 1000 in the digital camera 1020, it ispossible to take images subjected to optimum automatic color adjustmentaccording to memory colors and to store the images as files.

The video movie camera 1020 in accordance with this embodiment is anexample of a photographing apparatus in accordance with the presentinvention; the digital camera 1020 in accordance with this embodiment isan example of the photographing apparatus in accordance with the presentinvention; and the CCD 1021 is an example of a photographing means inaccordance with the present invention.

Next, the portable telephone 1030 shown in FIG. 17 will be described.

The portable telephone 1030 comprises an image processing apparatus1000, a wireless communication section 1031, a memory card 1032, a CCD1021, an A/D 1022, a selector 1035, a memory 1038, a camera controller1024, a photographing mode setting section 1025, an encoding means 1026,a memory card 1027 and a video display apparatus 1040.

The wireless communication section 1031 is a circuit having atransmission circuit of outputting transmission waves to an antenna anda receiving circuit of inputting received signals converted intoelectrical signals using the antenna and of demodulating image data andaudio data included in the received signals.

The memory card 1032 is a memory in which the image data received usingthe wireless communication section 1031 is stored.

The selector 1035 is a means of carrying out switching as to whether theimage data stored in the memory card 1032 is input or the image datataken using the CCD 1021 is input via the A/D 1022.

The memory 1036 is a means of temporarily storing the image data outputfrom the selector 1035.

The video display apparatus 1040 is a means of displaying the outputimage signal subjected to memory color conversion using the imageprocessing apparatus 1000 and comprises a liquid crystal displayapparatus or the like.

The CCD 1021, the A/D 1022, the camera controller 1024, thephotographing mode setting section 1025, the encoding means 1026 and thememory card 1027 are similar to those of the video movie camera 1020described referring to FIG. 16.

Although two memory cards, the memory card 1032 and the memory card1027, are shown in FIG. 17 as memory cards, the memory card 1032 and thememory card 1027 may be the same memory card.

Next, the operation of this kind of portable telephone 1030 will bedescribed.

The receiving circuit, not shown, of the wireless communication section1031 receives image data attached to e-mail and stores the data in thememory card 1032.

The selector 1035 reads the image data from the memory card 1032 andtemporarily stores the data in the memory 1036.

The image processing apparatus 1000 reads the image data temporarilystored in the memory card 1032 and carries out memory color conversion.

The output image signal subjected to memory color conversion using theimage processing apparatus 1000 is compressed and encoded using theencoding means 1026 and stored in the memory card 1027. In addition, theoutput image signal subjected to memory color conversion using the imageprocessing apparatus 1000 is displayed using the video display apparatus1040, such as a liquid crystal display apparatus.

The operation of subjecting the image data taken using the CCD 1021 tomemory color conversion is similar to that of the video movie camera1020 shown in FIG. 16, and its description is omitted.

When the image processing apparatus 1000 of the portable telephone 1030carries out memory color conversion, the correction degree can beobtained by using various photographic information described in theheader of an image file transmitted so as to be attached to e-mail orthe like, or information based on the camera user interface of thephotographing mode setting section 1025 and camera control information(focus, iris, etc.) as information other than pixel signals.

As described above, by incorporating the image processing apparatus 1000in the portable telephone 1030, it is possible to display imagessubjected to optimum automatic color adjustment according to memorycolors on a compact display or to store them in the memory card.

The portable telephone 1030 in accordance with this embodiment is anexample of a mobile communication terminal in accordance with thepresent invention; the wireless communication section 1031 in accordancewith this embodiment is an example of a wireless communication circuitin accordance with the present invention; and the video displayapparatus 1040 in accordance with this embodiment is an example of thedisplay means in accordance with the present invention.

The program of the present invention is a program that carries out thefunctions of all or part of the means (or apparatuses, devices, etc.) ofthe above-mentioned image processing apparatus of the present inventionusing a computer and operates in cooperation with the computer.

Still further, the recording medium of the present invention is arecording medium having a program that carries out all or part of thefunctions of all or part of the means (or apparatuses, devices, etc.) ofthe above-mentioned image processing apparatus of the present inventionusing a computer, the medium is readable using the computer, and theabove-mentioned program having been read from the recording medium isused to carry out the above-mentioned functions in cooperation with theabove-mentioned computer.

Still further, the above-mentioned “part of the means (or apparatuses,devices, etc.)” of the present invention is one or several means in themultiple means thereof.

Still further, the above-mentioned “the functions of the means (orapparatuses, devices, etc.)” of the present invention are all or part ofthe functions of the above-mentioned means.

Still further, one utilization form of the program of the presentinvention may be an embodiment that is recorded on a recording mediumreadable by a computer and operates in cooperation with the computer.

Still further, another utilization form of the program of the presentinvention may be an embodiment that is transmitted through atransmission medium, is read by a computer and operates in cooperationwith the computer.

Still further, the recording medium includes ROM and the like, and thetransmission medium includes a transmission medium, such as theInternet, light, electric wave, sound wave, etc.

Still further, the above-mentioned computer of the present invention isnot limited to pure hardware, such as a CPU, but may include firmware,OS and peripheral devices.

Still further, as described above, the configuration of the presentinvention may be attained by software or by hardware.

As described above, in accordance with the present invention, it ispossible to eliminate influence to objects other than the targetsubjected to memory color correction, and to reduce influence to theother objects in a memory color region while the continuity of gradationin the directions of luminance, saturation and hue in the memory colorregion and the boundary between the inside and outside of the memorycolor region is maintained. Furthermore, memory color correction havingvery few side effects can be attained by changing the correction degreedepending on whether an image requires memory color correction or not,whereby memory color correction operating fully automatically withoutrequiring the user to carry out judgment and setting can be attained.

As being clarified by the above descriptions, the present invention canprovide an image processing apparatus, an image processing method, aprogram, a program recording medium, a digital camera, a digitalcamcorder, a television receiver, a printer and a mobile communicationterminal not causing a side effect of correcting colors that should notbe subjected to memory color correction essentially.

Furthermore, the present invention can provide an image processingapparatus, an image processing method, a program, a program recordingmedium, a digital camera, a digital camcorder, a television receiver, aprinter and a mobile communication terminal capable of avoidingcorrecting other objects included in the memory color region that shouldbe corrected essentially but accidentally having colors close to thecolor to be corrected.

Still further, the present invention can provide an image processingapparatus, an image processing method, a program, a program recordingmedium, a digital camera, a digital camcorder, a television receiver, aprinter and a mobile communication terminal not making gradationdiscontinuous and not causing color jumping.

1. An image processing apparatus of correcting the color of apredetermined range of a pixel signal for each pixel included in aninput image signal, comprising: a target color setting unit which sets atarget color depending on which the color of said pixel signal iscorrected, and a color converter which carries out correction to makethe color of said pixel signal coincident with or close to said targetcolor by using a) said pixel signal, b) information of identifying aphotographic scene by also using photographic information, and c) saidtarget color, wherein said color converter comprises: an intensitydetermination unit which generates a correction intensity that issmaller on a periphery of a color region and larger in a vicinity of acentral portion of said color region, said color region having aspecific range set on the basis of two chromaticity components excludinga luminance component in the color of said pixel signal, a correctiondegree setting unit which sets a correction degree by using a) saidpixel signal, b) said information of identifying said photographicscene, and c) said target color, and a correction unit which makes thecolor of said pixel signal coincident with or close to said target colordepending on said correction intensity having been generated and saidcorrection degree having been set, wherein said correction degreesetting unit sets said correction degree by identifying at least animage photographing scene according to said input image signal.
 2. Theimage processing apparatus in accordance with claim 1, wherein saidcorrection degree setting unit determines said correction degreeaccording to said input image signal and photographic information at thetime when an input image is taken.
 3. The image processing apparatus inaccordance with claim 2, wherein said correction degree setting unitcomprises: an image identifier which identifies the photographic sceneof an image according to said input image signal, a photographicinformation identifier which identifies a photographic scene accordingto the photographic information at the time when said input image signalis photographed, and a correction degree determination unit whichdetermines said correction degree according to the outputs of said imageidentifier and said photographic information identifier.
 4. The imageprocessing apparatus in accordance with claim 3, wherein said imageidentifier and said photographic information identifier identify whethera person is included in an image or not.
 5. The image processingapparatus in accordance with claim 3, wherein said image identifier andsaid photographic information identifier identify whether the sky isincluded in an image or not.
 6. The image processing apparatus inaccordance with claim 3, wherein said image identifier and saidphotographic information identifier identify whether green plants areincluded in an image or not.
 7. An image processing apparatus ofcorrecting the color of a predetermined range of a pixel signal for eachpixel included in an input image signal, comprising: a target colorsetting unit which sets a target color depending on which the color ofsaid pixel signal is corrected, and a color converter which carries outcorrection to make the color of said pixel signal coincident with orclose to said target color by using a) the luminance component in thecolor of said pixel signal, b) two chromaticity components excludingsaid luminance component in the color of said pixel signal, and c) saidtarget value, wherein said color converter determines said correctiondegree by using not only said two chromaticity components of said pixelsignal to be corrected but also said luminance component of said pixelsignal to be corrected and, wherein said color converter comprises: anintensity determination unit which generates a correction intensity thatis smaller on a periphery of a color region and larger in a vicinity ofa central portion of said color region, said color region having aspecific range set on the basis of the luminance component and the twochromaticity components excluding said luminance component in the colorof said pixel signal, and a correction unit which makes the color ofsaid pixel signal coincident with or close to said target colordepending on said correction intensity having been generated.
 8. Animage processing apparatus in accordance with claim 7, wherein saidintensity determination unit comprises: a first function generator whichoutputs a candidate of a first correction intensity for said luminancesignal, second and third function generators which output candidates ofsecond and third correction intensities for said two chromaticitycomponents, respectively, and a synthesizer which synthesizes thecandidates of said first, second and third correction intensities andoutputs the result as said correction intensity.
 9. The image processingapparatus in accordance with claim 7, wherein said intensitydetermination unit comprises: a first function generator which outputs acandidate of a first correction intensity for said luminance signal, atwo-dimensional function generator which outputs a second correctionintensity on the basis of a two-dimensional function typified by anellipse using said two chromaticity components, and a synthesizer whichsynthesizes the candidates of said first and second correctionintensities and outputs the result as said correction intensity.
 10. Theimage processing apparatus in accordance with claim 7, wherein saidintensity determination unit comprises: a first function generator whichoutputs a candidate of a first correction intensity for said luminancesignal, a first polar coordinate converter which converts said twochromaticity components into a hue signal and a saturation signal, asecond function generator which generates a candidate of a secondcorrection intensity for said hue signal, a third function generatorwhich generates a candidate of a third correction intensity for saidsaturation signal, and a synthesizer which synthesizes the candidates ofsaid first, second and third correction intensities and outputs theresult as said correction intensity.
 11. The image processing apparatusin accordance with claim 1 or 7, wherein said correction unit correctseach of said two chromaticity components to a value obtained when eachof said two chromaticity components and two target chromaticity valuesoutput from said target color setting unit are internally divideddepending on said correction intensity.
 12. The image processingapparatus in accordance with claims 1 or 7, wherein said correction unithas a second polar coordinate converter which converts said twochromaticity components into a hue signal and a saturation signal andsaid saturation signal output from said second polar coordinateconverter being converted to a value obtained when said hue signal andsaid saturation signal and the target hue signal and the targetsaturation signal output from said target color setting unit areinternally divided depending on said correction intensity.
 13. The imageprocessing apparatus in accordance with claim 1 or 7, wherein saidintensity determination unit outputs a hue correction intensity for huecorrection and a saturation correction intensity for saturationcorrection, said correction unit has a second polar coordinate converterwhich converts said two chromaticity components into a hue signal and asaturation signal, a hue correction unit which corrects said hue signalhaving been converted to a value obtained when said hue signal and thetarget hue value output from said target color setting unit areinternally divided depending on said hue correction intensity, and asaturation correction unit which corrects said saturation signal havingbeen converted to a value obtained when said saturation signal and thetarget saturation value output from said target color setting unit areinternally divided depending on said saturation correction intensity.14. An image processing apparatus of correcting the color of apredetermined range of a pixel signal for each pixel included in aninput image signal, comprising: a target color setting unit which sets atarget color depending on which the color of said pixel signal iscorrected, a color converter which carries out correction to make thecolor of said pixel signal coincident with or close to said target colorby using a) said pixel signal, b) photographic information, and c) saidtarget color, and an interpolator which interpolates a three-dimensionallook-up table of using three input signals as addresses and outputsthree output signals or interpolates two of said three-dimensionallook-up tables, wherein the correspondence relationship of making thecolor of said pixel signal to correspond to the color corrected usingsaid color converter is stored in said three-dimensional look-up tablein advance, and the color of said each pixel signal is corrected usingsaid three-dimensional look-up table.
 15. An image processing apparatusof correcting the color of a predetermined range of a pixel signal foreach pixel included in an input image signal, comprising: a target colorsetting unit which sets a target color depending on which the color ofsaid pixel signal is corrected, a color converter which carries outcorrection to make the color of said pixel signal coincident with orclose to said target color by using a) the luminance component in thecolor of said pixel signal, b) two chromaticity components excludingsaid luminance component in the color of said pixel signal, and c) saidtarget value, and an interpolator which interpolates a three-dimensionallook-up table of using three input signals as addresses and outputsthree output signals or interpolates two of said three-dimensionallook-up tables, wherein said color converter determines said correctiondegree by using not only said two chromaticity components of said pixelsignal to be corrected but also said luminance component of said pixelsignal to be corrected, the correspondence relationship of making thecolor of said pixel signal to correspond to the color corrected usingsaid color converter is stored in said three-dimensional look-up tablein advance, and the color of said each pixel signal is corrected usingsaid three-dimensional look-up table.
 16. An image processing apparatusof correcting the color of a predetermined range of a pixel signal foreach pixel included in an input image signal, comprising: a target colorsetting unit which sets a target color depending on which the color ofsaid pixel signal is corrected, an intensity determination unit whichgenerates a correction intensity on the basis of at least onechromaticity component, among the luminance component and the twochromaticity components in the color of said pixel signal, aphotographic image information identifier which identifies whether anobject as a target of a correction of color is included or not for eachinput image, the photographic image information identifier identifyingaccording to photographic information at the time when the input imageis taken, a correction degree determination unit which determines acorrection degree for each input image, according to the output of saidphotographic image information identifier and a correction unit whichcorrects the color of said pixel signal according to said correctionintensity generated for each pixel and said correction degree determinedfor each input image, wherein said correction unit performs a correctionof said color of said pixel signal so that a difference between saidtarget color and said color becomes smaller after the correction thanbefore the correction.
 17. The image processing apparatus according toclaim 16, wherein said photographic image information identifieridentifies, according to a distance to object(s) of said photographicinformation, as to whether a person who is able to be considered as aprimary object based on its size is included or not in said input image.18. The image processing apparatus according to claim 17, wherein saidphotographic image information identifier identifies the person who isable to be considered as the primary object based on its size is notincluded in said input image in the case that the distance to saidobject(s) is a distance of macro view or a distance of distant view. 19.The image processing apparatus according to claim 16, wherein saidphotographic image information identifier identifies, according to aninformation of said photographic information regarding flash light, aperson who is able to be considered as a primary object based on itssize is not included in said input image in the case that the flashlight is emitted and its returned light is not detected.
 20. The imageprocessing apparatus according to claim 19, wherein the detection ofsaid returned light is performed so as to be judged that said returnedlight was not detected when the luminance at a central portion in saidimage was not relatively high.
 21. The image processing apparatusaccording to claim 19, wherein the detection/non-detection of saidreturned light is judged according to the information recorded in saidphotographic information.
 22. The image processing apparatus accordingto claim 19, where said photographic image information identifieridentifies, according to an information of said photographic informationregarding a light source, as to whether a sky is to be included or notin said input image.
 23. The image processing apparatus according toclaim 22, wherein said photographic image information identifieridentifies the sky is not included in said input image in the case thatsaid information regarding the light source indicates said light sourceis an indoor light.
 24. The image processing apparatus according toclaim 16, wherein said photographic image information identifieridentifies, according to a photographing time of said photographicinformation, as to whether a sky is to be included or not in said inputimage.
 25. The image processing apparatus according to claim 16, whereinsaid photographic image information identifier identifies, according toan estimated brightness of the object, that a sky is not included insaid input image in the case that the estimated brightness is lower thana predetermined value, and the estimated brightness is estimatedaccording to a shutter speed and a aperture value both of which areincluded in said photographic information.
 26. The image processingapparatus according to claim 16, wherein said photographic imageinformation identifier identifies, according to a photographic sceneinformation of said photographic information, as to whether a person isincluded or not in said input image.